Draft: Clean up github_user_mapping feature flag

Carla Dragorequested to merge
510963-cleanup-github-user-mapping-ff into master

What does this MR do and why?

This cleans up the github_user_mapping feature flag removing the yml file and relevant code.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #510963

Merge request reports