Cleanup feature flag: security_incident_rollback_checks

Feature flag cleanup: security_incident_rollback_checks

Description

This issue tracks the cleanup of the security_incident_rollback_checks feature flag that was implemented in #20923 (closed).

Background

The feature flag is currently defined at https://ops.gitlab.net/gitlab-org/release/tools/-/feature_flags and is used in the Rollback::Comparison class to conditionally check for security and incident MRs during rollback operations.

Tasks

• Verify the feature is working correctly in production.
• Remove the feature flag checks from the codebase:
  • Remove the feature flag check in ReleaseTools::Rollback::Comparison#execute (https://gitlab.com/gitlab-org/release-tools/-/blob/master/lib/release_tools/rollback/comparison.rb)
  • Remove any other conditional logic related to this feature flag
• Remove the feature flag definition from the feature flags configuration at https://ops.gitlab.net/gitlab-org/release/tools/-/feature_flags
• Update tests to remove feature flag related test cases

Definition of Done

• The feature flag has been completely removed from the codebase
• The functionality works correctly without the feature flag
• All tests pass