Reset status cache when status_stat or media_attachment updates (#9119)

* Reset status cache when status_stat or media_attachment updates

Fix #8711

Media attachments are generally immutable, but admins can update
the sensitive flag, and this would ensure the change is visible
instantly. Same for updates to status stats. That is a regression
from #8185, because even the correct updated_at fetched from a join
doesn't seem to invalidate the cache.

* Remove join from Status#cache_ids since it has no effect

app/models/status.rb

@@ -240,10 +240,6 @@ class Status < ApplicationRecord
   before_validation :set_local
 
   class << self
-    def cache_ids
-      left_outer_joins(:status_stat).select('statuses.id, greatest(statuses.updated_at, status_stats.updated_at) AS updated_at')
-    end
-
     def selectable_visibilities
       visibilities.keys - %w(direct limited)
     end