Enable prevent_retry_of_retried_jobs feature flag on by default

This has been enabled by default on GitLab.com for a week and has
thwarted a significant amount of CI abuse.

Relates to https://gitlab.com/gitlab-org/gitlab/-/issues/331695

Changelog: changed

config/feature_flags/development/prevent_retry_of_retried_jobs.yml

@@ -5,4 +5,4 @@ rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/331695
 milestone: '14.0'
 type: development
 group: group::continuous integration
-default_enabled: false
+default_enabled: true