Ensure handlers have proper parent (#39426)

* Ensure role handlers are parented correctly. Fixes #36518

* Add delegate_to test for include_role handlers

lib/ansible/playbook/role_include.py

@@ -96,6 +96,8 @@ class IncludeRole(TaskInclude):
 
         # updated available handlers in play
         handlers = actual_role.get_handler_blocks(play=myplay)
+        for h in handlers:
+            h._parent = self
         myplay.handlers = myplay.handlers + handlers
         return blocks, handlers