RuboCop: Fix silenced offenses issues

What does this MR do and why?

This MR fixes silenced offenses like https://gitlab.com/gitlab-org/gitlab/-/jobs/3115984225#L670 by:

• Regenerating RuboCop TODOs for RSpec/MultipleMemoizedHelpers
  • Added via !99289 (merged)
• Disable Lint/RedundantCopDisableDirective again and investigate (follow-up issue)

How to set up and validate locally

bundle exec rake rubocop:check:graceful

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.