Merge branch 'ph/429557/enableMrRequestChangesFlag' into 'master'

Enables mr_request_changes by default

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/143384



Merged-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Approved-by: Natalia Tepluhina <ntepluhina@gitlab.com>
Co-authored-by: Phil Hughes <me@iamphill.com>