Fix Sidekiq warnings about JSON serialization (#17381)

* Fix Sidekiq warnings about JSON serialization

This occurs on every symbol argument we pass, and every symbol key in hashes,
because Sidekiq expects strings instead.

See https://github.com/mperham/sidekiq/pull/5071

We do not need to change how workers parse their arguments because this has
not changed and we were already converting to symbols adequately or using
`with_indifferent_access`.

* Set Sidekiq to raise on unsafe arguments in test mode

In order to more easily catch issues that would produce warnings in production
code.

app/lib/activitypub/activity/create.rb

@@ -94,7 +94,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
     LinkCrawlWorker.perform_in(rand(1..59).seconds, @status.id)
 
     # Distribute into home and list feeds and notify mentioned accounts
-    ::DistributionWorker.perform_async(@status.id, silenced_account_ids: @silenced_account_ids) if @options[:override_timestamps] || @status.within_realtime_window?
+    ::DistributionWorker.perform_async(@status.id, { 'silenced_account_ids' => @silenced_account_ids }) if @options[:override_timestamps] || @status.within_realtime_window?
   end
 
   def find_existing_status
@@ -168,7 +168,7 @@ class ActivityPub::Activity::Create < ActivityPub::Activity
 
     return unless delivered_to_account.following?(@account)
 
-    FeedInsertWorker.perform_async(@status.id, delivered_to_account.id, :home)
+    FeedInsertWorker.perform_async(@status.id, delivered_to_account.id, 'home')
   end
 
   def delivered_to_account