Refs #35744 -- Removed problematic __in lookup in test_intersection_in_nested_subquery.

It's problematic on MongoDB. Simon: "It seems odd that we'd use
__in=OuterRef("pk") over __in=[OuterRef("pk")]. It's a SQLism that
only works because right-hand-side is wrapped with (...) and that's
interpreted as a singleton tuple which is allowed with IN."

tests/queries/test_qs_combinators.py

@@ -512,12 +512,7 @@ class QuerySetSetOperationTests(TestCase):
             tags.filter(id=OuterRef(OuterRef("tag_id")))
         )
         qs = Note.objects.filter(
-            Exists(
-                Annotation.objects.filter(
-                    Exists(tags),
-                    notes__in=OuterRef("pk"),
-                )
-            )
+            Exists(Annotation.objects.filter(Exists(tags), notes=OuterRef("pk")))
         )
         self.assertIsNone(qs.first())
         annotation.notes.add(note)