Merge branch 'master' into glitch-soc/merge-upstream

Conflicts:
- `app/javascript/mastodon/features/compose/components/poll_form.js`:
  Upstream bumped poll option character limit, but we already had
  a higher one, kept ours.
- `app/validators/poll_validator.rb`:
  Upstream bumped poll option character limit, but we already had
  a higher one, kept ours.
- `config/initializers/content_security_policy.rb`:
  Upstream added a rule, the way we compute ours is different, but
  that added rule has been ported.
- `package.json`:
  No real conflict, dependency update. Performed the same update.
- `yarn.lock`:
  No real conflict, dependency update. Performed the same update.

app/workers/scheduler/feed_cleanup_scheduler.rb

@@ -4,7 +4,7 @@ class Scheduler::FeedCleanupScheduler
   include Sidekiq::Worker
   include Redisable
 
-  sidekiq_options unique: :until_executed, retry: 0
+  sidekiq_options lock: :until_executed, retry: 0
 
   def perform
     clean_home_feeds!