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.

config/routes.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-require 'sidekiq/web'
+require 'sidekiq_unique_jobs/web'
 require 'sidekiq-scheduler/web'
 
 Sidekiq::Web.set :session_secret, Rails.application.secrets[:secret_key_base]