Merge branch 'improve-group-work-items-query' into 'master'

Improve performance of group work items query

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/141973



Merged-by: Andy Soiron <asoiron@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Approved-by: Andy Soiron <asoiron@gitlab.com>
Co-authored-by: Heinrich Lee Yu <heinrich@gitlab.com>

app/finders/issues_finder.rb

@@ -118,7 +118,7 @@ def by_parent(items)
     namespaces = if relations.one?
                    relations.first
                  else
-                   Namespace.from_union(relations, remove_duplicates: false)
+                   Namespace.from_union(relations)
                  end
 
     items.in_namespaces(namespaces)