Add Sidekiq shard-support for active jobs

What does this MR do and why?

This MR adds Sidekiq shard-support for active jobs. This primarily affects MailDeliveryJob enqueues by ActionMailer.

See gitlab-com/gl-infra/scalability#2817 (comment 1845599786)

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Before	After

How to set up and validate locally

1. Disable sidekiq workers using

gdk stop rails-background-jobs

2. Start a local docker for Redis

docker run -p 6378:6379 -d redis:6.2-alpine

3. Update config files

➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ cat config/redis.yml
---
development:
  queues_shard_catchall_a:
    url: "redis://localhost:6378"

➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ cat config/feature_flags/worker/sidekiq_route_to_queues_shard_catchall_a.yml
---
name: sidekiq_route_to_queues_shard_catchall_a
feature_issue_url: https://gitlab.com/groups/gitlab-com/gl-infra/-/epics/1218
introduced_by_url:
rollout_issue_url:
milestone: '16.11'
group: group::scalability
type: worker
default_enabled: false

Also update config/gitlab.yml with:

## Sidekiq
  sidekiq:
    log_format: json # (default is also supported)
    routing_rules:
      - ["tags=needs_own_queue", null]
      - ["worker_name=ActionMailer::MailDeliveryJob", "mailer", "queues_shard_catchall_a"]
      - ["*", "default"]

2. On this branch, open a rails console and enqueue a mail job

[1] pry(main)> Feature.enable(:enable_sidekiq_shard_router)
[2] pry(main)> Notify.note_issue_email(User.first.id, Note.first.id).deliver_later

3. Verify that this shows up in the gdk Redis

➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ gdk redis-cli -n 1 lrange queue:mailers 0 -1
1) "{\"retry\":3,\"queue\":\"mailers\",\"backtrace\":true,\"store\":\"queues_shard_catchall_a\",\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::MailDeliveryJob\",\"args\":[{\"job_class\":\"ActionMailer::MailDeliveryJob\",\"job_id\":\"15b5c62a-7eee-416b-98f8-51f9b8975ae9\",\"provider_job_id\":null,\"queue_name\":\"mailers\",\"priority\":null,\"arguments\":[\"Notify\",\"note_issue_email\",\"deliver_now\",{\"args\":[1,1],\"_aj_ruby2_keywords\":[\"args\"]}],\"executions\":0,\"exception_executions\":{},\"locale\":\"en\",\"timezone\":\"UTC\",\"enqueued_at\":\"2024-04-04T08:20:54Z\"}],\"jid\":\"d5e241ad17cccc0a9971cd0f\",\"created_at\":1712218854.333045,\"correlation_id\":\"874d597596f063bdb8adc47a51fd4597\",\"worker_data_consistency\":\"delayed\",\"wal_locations\":{},\"wal_location_source\":\"primary\",\"idempotency_key\":\"resque:gitlab:duplicate:mailers:57bb2acb944153ad0f7b6c9ed0c69f38ec0ce1543bf009e2a9989e49d9d02d23\",\"size_limiter\":\"validated\",\"enqueued_at\":1712218854.3536398}"
➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ redis-cli -p 6378 lrange queue:mailers 0 -1
(empty array)

4. Enable the feature flag and send another mail job.

[4] pry(main)> Feature.enable(:sidekiq_route_to_queues_shard_catchall_a)
[5] pry(main)> Notify.note_issue_email(User.first.id, Note.first.id).deliver_later

5. Verify that the 2nd message goes to the docker Redis

➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ gdk redis-cli -n 1 lrange queue:mailers 0 -1
1) "{\"retry\":3,\"queue\":\"mailers\",\"backtrace\":true,\"store\":\"queues_shard_catchall_a\",\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::MailDeliveryJob\",\"args\":[{\"job_class\":\"ActionMailer::MailDeliveryJob\",\"job_id\":\"15b5c62a-7eee-416b-98f8-51f9b8975ae9\",\"provider_job_id\":null,\"queue_name\":\"mailers\",\"priority\":null,\"arguments\":[\"Notify\",\"note_issue_email\",\"deliver_now\",{\"args\":[1,1],\"_aj_ruby2_keywords\":[\"args\"]}],\"executions\":0,\"exception_executions\":{},\"locale\":\"en\",\"timezone\":\"UTC\",\"enqueued_at\":\"2024-04-04T08:20:54Z\"}],\"jid\":\"d5e241ad17cccc0a9971cd0f\",\"created_at\":1712218854.333045,\"correlation_id\":\"874d597596f063bdb8adc47a51fd4597\",\"worker_data_consistency\":\"delayed\",\"wal_locations\":{},\"wal_location_source\":\"primary\",\"idempotency_key\":\"resque:gitlab:duplicate:mailers:57bb2acb944153ad0f7b6c9ed0c69f38ec0ce1543bf009e2a9989e49d9d02d23\",\"size_limiter\":\"validated\",\"enqueued_at\":1712218854.3536398}"
➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ redis-cli -p 6378 lrange queue:mailers 0 -1
1) "{\"retry\":3,\"queue\":\"mailers\",\"backtrace\":true,\"store\":\"queues_shard_catchall_a\",\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::MailDeliveryJob\",\"args\":[{\"job_class\":\"ActionMailer::MailDeliveryJob\",\"job_id\":\"5e1a6e35-e218-41c3-bb1a-62daf60fd97f\",\"provider_job_id\":null,\"queue_name\":\"mailers\",\"priority\":null,\"arguments\":[\"Notify\",\"note_issue_email\",\"deliver_now\",{\"args\":[1,1],\"_aj_ruby2_keywords\":[\"args\"]}],\"executions\":0,\"exception_executions\":{},\"locale\":\"en\",\"timezone\":\"UTC\",\"enqueued_at\":\"2024-04-04T08:21:36Z\"}],\"jid\":\"9fca77caed5730f3d2548ddb\",\"created_at\":1712218896.535786,\"correlation_id\":\"1a8f4a556579b9e7b5ee10e0403f221e\",\"worker_data_consistency\":\"delayed\",\"wal_locations\":{},\"wal_location_source\":\"primary\",\"idempotency_key\":\"resque:gitlab:duplicate:mailers:1d309117c817a468d185aa0ebf103f5fcff7812798cf485099ae8560ca0f5601\",\"size_limiter\":\"validated\",\"enqueued_at\":1712218896.5486012}"

6. Repeat the steps on the master branch

➜  gitlab git:(sc1-maildelivery-shard-awareness) ✗ redis-cli -p 6378  del queue:mailers
(integer) 1
➜  gitlab git:(master) ✗ gdk redis-cli -n 1 del queue:mailers
(integer) 1

Even with the ff enabled:

[2] pry(main)> Feature.enabled?(:sidekiq_route_to_queues_shard_catchall_a)
=> true
[3] pry(main)> Notify.note_issue_email(User.first.id, Note.first.id).deliver_later

The message is sent to the gdk Redis.

➜  gitlab git:(master) ✗ redis-cli -p 6378 lrange queue:mailers 0 -1
(empty array)
➜  gitlab git:(master) ✗ gdk redis-cli -n 1 lrange queue:mailers 0 -1
1) "{\"retry\":3,\"queue\":\"mailers\",\"backtrace\":true,\"class\":\"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper\",\"wrapped\":\"ActionMailer::MailDeliveryJob\",\"args\":[{\"job_class\":\"ActionMailer::MailDeliveryJob\",\"job_id\":\"01eaec10-70fe-4c35-b7a8-b2cedd94fe96\",\"provider_job_id\":null,\"queue_name\":\"mailers\",\"priority\":null,\"arguments\":[\"Notify\",\"note_issue_email\",\"deliver_now\",{\"args\":[1,1],\"_aj_ruby2_keywords\":[\"args\"]}],\"executions\":0,\"exception_executions\":{},\"locale\":\"en\",\"timezone\":\"UTC\",\"enqueued_at\":\"2024-04-04T08:23:37Z\"}],\"jid\":\"cb3f4db3d7088c1cab659e26\",\"created_at\":1712219017.578569,\"correlation_id\":\"02c689d8480b40170ae596c0535a301e\",\"worker_data_consistency\":\"delayed\",\"wal_locations\":{},\"wal_location_source\":\"primary\",\"idempotency_key\":\"resque:gitlab:duplicate:mailers:392a54c377bd477f02c4a090fe7ec5bd2c5a264c5d925be8fc0e25198685d387\",\"size_limiter\":\"validated\",\"enqueued_at\":1712219017.587424}"