* Fix being able to import more than allowed number of follows

Without this commit, if someone tries importing a second list of accounts to
follow before the first one has been processed, this will queue imports for
the two whole lists, even if they exceed the account's allowed number of
outgoing follows.

This commit changes it so the individual queued imports aren't exempt from
the follow limit check (they remain exempt from the rate-limiting check
though).

* Catch validation errors to not re-queue failed follows

Co-authored-by: Claire <claire.github-309c@sitedethib.com>

* Add bell button

Fix #4890

* Remove duplicate type from post-deployment migration

* Fix legacy class type mappings

* Improve query performance with better index

* Fix validation

* Remove redundant index from notifications

* Fix RefollowWorker not keeping show_reblogs setting

* Fix RefollowWorker