Merge branch 'eread/use-full-url-for-ff-mr' into 'master'

Use full URL for feature flag MR

See merge request gitlab-org/gitlab!60456

ee/config/feature_flags/development/geo_secondary_proxy.yml

 ---
 name: geo_secondary_proxy
-introduced_by_url: '56297'
+introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/56297
 rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/325732
 milestone: '13.11'
 type: development