RSpec/MultipleMemoizedHelpers: Move pending offenses into .rubocop_todo/

What does this MR do and why?

This MR moves current offenses for 👮 RSpec/MultipleMemoizedHelpers from .rubocop.yml to .rubocop_todo/. Temporary exclusions should be placed there. It removes the exclusions of spec/migrations/**/*.rb.

It also lowers Max from 28 to 25 to bring it close to 20, 10 and 5 eventually 😅

See prior art: !55211 (merged)

Console output

Before

$ REVEAL_RUBOCOP_TODO=0 be rubocop --show-cops | grep -A 10 RSpec/MultipleMemoizedHelpers
RSpec/MultipleMemoizedHelpers:
  Description: Checks if example groups contain too many `let` and `subject` calls.
  Enabled: true
  AllowSubject: true
  Max: 28
  VersionAdded: '1.43'
  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers
  Exclude:
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/migrations/**/*.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/populate_project_snippet_statistics_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/populate_finding_uuid_for_vulnerability_feedback_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/gitlab/background_migration/user_mentions/create_resource_user_mention_spec.rb"

After

RSpec/MultipleMemoizedHelpers:
  Description: Checks if example groups contain too many `let` and `subject` calls.
  Enabled: true
  AllowSubject: true
  Max: 25
  VersionAdded: '1.43'
  StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers
  Exclude:
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/populate_finding_uuid_for_vulnerability_feedback_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/recalculate_vulnerabilities_occurrences_uuid_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/diff/position_tracer/line_strategy_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/requests/api/ci/runner/jobs_artifacts_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/ee/gitlab/background_migration/populate_latest_pipeline_ids_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/services/ee/boards/issues/move_service_spec.rb"
  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/services/security/store_report_service_spec.rb"

Diff

--- before	2022-01-31 17:23:32.587446747 +0100
+++ after	2022-01-31 17:23:35.675555531 +0100
@@ -2,12 +2,15 @@
   Description: Checks if example groups contain too many `let` and `subject` calls.
   Enabled: true
   AllowSubject: true
-  Max: 28
+  Max: 25
   VersionAdded: '1.43'
   StyleGuide: https://www.rubydoc.info/gems/rubocop-rspec/RuboCop/Cop/RSpec/MultipleMemoizedHelpers
   Exclude:
-  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/migrations/**/*.rb"
-  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/populate_project_snippet_statistics_spec.rb"
   - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/populate_finding_uuid_for_vulnerability_feedback_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/background_migration/recalculate_vulnerabilities_occurrences_uuid_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/lib/gitlab/diff/position_tracer/line_strategy_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/spec/requests/api/ci/runner/jobs_artifacts_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/ee/gitlab/background_migration/populate_latest_pipeline_ids_spec.rb"
   - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/ee/gitlab/background_migration/populate_uuids_for_security_findings_spec.rb"
-  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/lib/gitlab/background_migration/user_mentions/create_resource_user_mention_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/services/ee/boards/issues/move_service_spec.rb"
+  - "/home/peter/devel/gitlab/gdk-ee/gitlab/ee/spec/services/security/store_report_service_spec.rb"

How to set up and validate locally

REVEAL_RUBOCOP_TODO=1 bundle exec rubocop -p --only RSpec/MultipleMemoizedHelpers spec ee/spec

REVEAL_RUBOCOP_TODO=0 bundle exec rubocop -p --only RSpec/MultipleMemoizedHelpers spec ee/spec

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.