Fix Style/MultipleComparison (#33313)

Co-authored-by: Matt Jankowski <matt@jankowski.online>

app/lib/activitypub/tag_manager.rb

@@ -13,7 +13,7 @@ class ActivityPub::TagManager
   }.freeze
 
   def public_collection?(uri)
-    uri == COLLECTIONS[:public] || uri == 'as:Public' || uri == 'Public'
+    uri == COLLECTIONS[:public] || %w(as:Public Public).include?(uri)
   end
 
   def url_for(target)