Merge branch '384359-remove-ff-ci_bridge_remove_sourced_pipelines' into 'master'

Remove `ci_bridge_remove_sourced_pipelines` feature flag

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/107121



Merged-by: Dylan Griffith <dyl.griffith@gmail.com>
Approved-by: drew stachon <730684-drew@users.noreply.gitlab.com>
Approved-by: Dylan Griffith <dyl.griffith@gmail.com>
Co-authored-by: lma-git <lma@gitlab.com>