Ensure handlers have proper parent (#39426)

* Ensure role handlers are parented correctly. Fixes #36518

* Add delegate_to test for include_role handlers

test/integration/targets/include_import/role/test_import_role.yml

@@ -136,3 +136,8 @@
         - name: Include role inside always
           import_role:
             name: role3
+
+    - name: Test delegate_to handler is delegated
+      import_role:
+        name: delegated_handler
+      delegate_to: localhost

test/integration/targets/include_import/roles/delegated_handler/handlers/main.yml

@@ -0,0 +1,4 @@
+- name: delegated assert handler
+  assert:
+    that:
+      - ansible_delegated_vars is defined

test/integration/targets/include_import/roles/delegated_handler/tasks/main.yml

@@ -0,0 +1,3 @@
+- command: "true"
+  notify:
+    - delegated assert handler