Reduced instantiations in loop

Lowers the number of variables instantiated when sorting a
potentially very large set of tags.

app/models/repository.rb

@@ -1165,17 +1165,13 @@ class Repository
   end
 
   def tags_sorted_by_committed_date
-    tags.sort_by do |tag|
     # Annotated tags can point to any object (e.g. a blob), but generally
     # tags point to a commit. If we don't have a commit, then just default
     # to putting the tag at the end of the list.
-      target = tag.dereferenced_target
+    default = Time.current
 
-      if target
-        target.committed_date
-      else
-        Time.current
-      end
+    tags.sort_by do |tag|
+      tag.dereferenced_target&.committed_date || default
     end
   end