Do not allow addressing an import from handlers via notify. Fixes #48936 (#49317)

test/integration/targets/include_import/handler_addressing/playbook.yml

@@ -0,0 +1,11 @@
+- hosts: localhost
+  gather_facts: false
+  tasks:
+    - import_role:
+        name: include_handler_test
+
+- hosts: localhost
+  gather_facts: false
+  tasks:
+    - import_role:
+        name: import_handler_test

test/integration/targets/include_import/handler_addressing/roles/import_handler_test/handlers/main.yml

@@ -0,0 +1,2 @@
+- name: do_import
+  import_tasks: tasks/handlers.yml

test/integration/targets/include_import/handler_addressing/roles/import_handler_test/tasks/handlers.yml

@@ -0,0 +1,2 @@
+- debug:
+    msg: import handler task

test/integration/targets/include_import/handler_addressing/roles/import_handler_test/tasks/main.yml

@@ -0,0 +1,3 @@
+- command: "true"
+  notify:
+    - do_import

test/integration/targets/include_import/handler_addressing/roles/include_handler_test/handlers/main.yml

@@ -0,0 +1,2 @@
+- name: do_include
+  include_tasks: tasks/handlers.yml

test/integration/targets/include_import/handler_addressing/roles/include_handler_test/tasks/handlers.yml

@@ -0,0 +1,2 @@
+- debug:
+    msg: include handler task

test/integration/targets/include_import/handler_addressing/roles/include_handler_test/tasks/main.yml

@@ -0,0 +1,3 @@
+- command: "true"
+  notify:
+    - do_include

test/integration/targets/include_import/runme.sh

@@ -86,3 +86,7 @@ ansible-playbook public_exposure/no_overwrite_roles.yml -i ../../inventory "$@"
 
 # https://github.com/ansible/ansible/pull/48068
 ansible-playbook run_once/playbook.yml "$@"
+
+# https://github.com/ansible/ansible/issues/48936
+ansible-playbook -v handler_addressing/playbook.yml 2>&1 | tee test_handler_addressing.out
+test "$(egrep -c 'include handler task|ERROR! The requested handler '"'"'do_import'"'"' was not found' test_handler_addressing.out)" = 2