[stable-2.7] Fix return statement where we short circuit _get_delegated_vars (#48102)

(cherry picked from commit cb5626c)

Co-authored-by: Matt Martz <matt@sivel.net>

changelogs/fragments/loop-cache-include-apply.yml

@@ -0,0 +1,2 @@
+bugfixes:
+- delegate_to - Fix issue where delegate_to was upplied via ``apply`` on an include, where a loop was present on the include

lib/ansible/vars/manager.py

@@ -489,7 +489,7 @@ class VariableManager:
     def _get_delegated_vars(self, play, task, existing_variables):
         if not hasattr(task, 'loop'):
             # This "task" is not a Task, so we need to skip it
-            return {}
+            return {}, None
 
         # we unfortunately need to template the delegate_to field here,
         # as we're fetching vars before post_validate has been called on