[Documentation] Update feature status of external status checks

doc/user/project/merge_requests/status_checks.md

@@ -11,9 +11,6 @@ disqus_identifier: 'https://docs.gitlab.com/ee/user/project/merge_requests/statu
 > - [Introduced](https://gitlab.com/groups/gitlab-org/-/epics/3869) in GitLab 14.0, disabled behind the `:ff_external_status_checks` feature flag.
 > - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/issues/320783) in GitLab 14.1.
 
-WARNING:
-This feature might not be available to you. Check the **version history** note above for details.
-
 You can create a status check that sends merge request data to third-party tools.
 When users create, change, or close merge requests, GitLab sends a notification. The users or automated workflows
 can then update the status of merge requests from outside of GitLab.