Fix scheduled statuses decreasing statuses counts (#16791)

* Add tests

* Fix scheduled statuses decreasing statuses counts

Fixes #16774

app/models/status.rb

@@ -426,7 +426,7 @@ class Status < ApplicationRecord
   end
 
   def decrement_counter_caches
-    return if direct_visibility?
+    return if direct_visibility? || new_record?
 
     account&.decrement_count!(:statuses_count)
     reblog&.decrement_count!(:reblogs_count) if reblog?

app/services/post_status_service.rb

@@ -74,6 +74,9 @@ class PostStatusService < BaseService
     status_for_validation = @account.statuses.build(status_attributes)
 
     if status_for_validation.valid?
+      # Marking the status as destroyed is necessary to prevent the status from being
+      # persisted when the associated media attachments get updated when creating the
+      # scheduled status.
       status_for_validation.destroy
 
       # The following transaction block is needed to wrap the UPDATEs to