backport.py: Restore included_in branches check
- Restores check for included-in branches, which is used when confirming backports in the case a dependency was previously merged into a non-production branch, but the resulting commit eventually got included in a production branch. For example:
- Change A to operations/mediawiki-config master depends on Change B to mediawiki/core master
- Change B is merged into master and subsequently a train branch is cut and deployed.
- Adds integration test for included-in branches check
- Errors out when a change for backport is not deployable and removes any related integration tests
- In wait_for_changes_to_be_merged, checks revision number directly instead of revisions[revision]["_number"]
Related MRs:
https://gitlab.wikimedia.org/repos/releng/train-dev/-/merge_requests/71