* Remove obsolete RSS::Serializer test
Since #17828, RSS::Serializer no longer has specific code for deleted statuses,
but it is never called on deleted statuses anyway.
* Rename erroneously-named test files
* Fix failing test
* Fix test deprecation warnings
* Update CircleCI Ruby orb
1.4.0 has a bug that does not match all the test files due to incorrect
globbing
* Add account_notes relationship
* Add tests
* Fix owned account notes not being deleted when an account is deleted
* Add post-migration to clean up orphaned account notes
* Fix deleting polls not deleting notifications
* Fix fav notification deletion when deleting a toot
* Refactor DeleteAccountService spec
* Add DeleteAccountService tests for other associations and notifications
* Add favourite handling spec in status removal
Co-authored-by: Claire <claire.github-309c@sitedethib.com>