[FF] `ai_experiment_sast_fp_detection` - Cleanup
## Summary
This issue is to clean up the `ai_experiment_sast_fp_detection` feature flag that has been rolled out and is now stable.
## Cleanup Steps
- [ ] Create a merge request to remove the `ai_experiment_sast_fp_detection` feature flag. Ask for review/approval/merge as usual. The MR should include the following changes:
- Remove all references to the feature flag from the codebase.
- Remove the YAML definitions for the feature from the repository.
- [ ] Ensure that the cleanup MR has been included in the release package.
If the merge request was deployed before [the monthly release was tagged](https://about.gitlab.com/handbook/engineering/releases/#self-managed-releases-1),
the feature can be officially announced in a release blog post: `/chatops run release check <merge-request-url> <milestone>`
- [ ] Once the cleanup MR has been deployed to production, clean up the feature flag from all environments by running these chatops command in `#production` channel: `/chatops run feature delete ai_experiment_sast_fp_detection --dev --pre --staging --staging-ref --production`
- [ ] Close the related rollout issue #583674.
## Related Issues
- Rollout issue: #583674
issue