Add more context to sidekiq deprecation notice messages

What does this MR do?

The sidekiq.pods has some deprecated keys which are checked in gitlab.deprecations. The first line of the deprecation notice currently provides no context about the subchart the deprecation belongs to.

This MR changes the first line this context. The syntax is introduced in !2969 (merged) for a sidekiq.pod deprecations.

Related issues

None

Test Plan

Deploy the Helm Chart with:

global:
  hosts:
    domain: redacted # use a real domain here
certmanager-issuer:
  email: redacted # use your real email address here

gitlab:
  sidekiq:
    pods:
      - name: all-in-1
        cluster:
          foo: bar
        updateStrategy: barfoo

The installation should fail with the following message:

DEPRECATIONS:
sidekiq.pods[0] (all-in-1):
    The configuration of 'gitlab.sidekiq.pods[0].updateStrategy' has moved. Please use 'gitlab.sidekiq.pods[0].deployment.strategy' instead.
sidekiq.pods[0] (all-in-1):
    The configuration of 'gitlab.sidekiq.pods[0].cluster' should be removed. Sidekiq is now always in cluster mode.

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion.

Required

• Merge Request Title and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• When ready for review, MR is labeled "~workflow::ready for review" per the Distribution MR workflow

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
  • not applicable
• Tests added
  • not applicable
• Integration tests added to GitLab QA
  • not applicable
• Equivalent MR/issue for omnibus-gitlab opened
  • not applicable
• Validate potential values for new configuration settings. Formats such as integer 10, duration 10s, URI scheme://user:passwd@host:port may require quotation or other special handling when rendered in a template and written to a configuration file.
  • not applicable