Update Redis::SharedState to be Cluster compatible

What does this MR do and why?

This MR updates Gitlab::Redis::SharedState callsites to be compatible with Redis Cluster.

Continuation from !124256 (closed)

Refer to gitlab-com/gl-infra/scalability#2193 (closed)

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Before	After

How to set up and validate locally

1. Set up GDK on the master branch with config/redis.yml configured to use a Redis Cluster

➜  gitlab git:(master) ✗ cat ../gdk.yml
---
redis_cluster:
  enabled: true

➜  gitlab git:(sc1-deprecate-namespace) ✗ cat config/redis.yml
---
test:
  shared_state:
    cluster:
      - "redis://localhost:6003"
      - "redis://localhost:6004"
      - "redis://localhost:6005"

2. Run some affected specs

bin/rspec spec/lib/gitlab/sidekiq_status_spec.rb

You should get errors like:

 Failure/Error: raise RedisClusterValidator::CrossSlotError, "Redis command #{result[:command_name]} arguments hash to different slots. See https://docs.gitlab.com/ee/development/redis.html#multi-key-commands"

     Gitlab::Instrumentation::RedisClusterValidator::CrossSlotError:
       Redis command MGET arguments hash to different slots. See https://docs.gitlab.com/ee/development/redis.html#multi-key-commands

Repeat the specs on this branch.

MR acceptance checklist

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