Merge branch 'ph/341809/defaultEnableDiffsFluidFlag' into 'master'

Enables the mr_changes_fluid_layout flag by default

See merge request gitlab-org/gitlab!73261

config/feature_flags/development/mr_changes_fluid_layout.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/341809
 milestone: '14.4'
 type: development
 group: group::code review
-default_enabled: false
+default_enabled: true