update role to provide better error messages (#12599)

awx_collection/tests/integration/targets/role/tasks/main.yml

@@ -121,6 +121,22 @@
         that:
           - "result is changed"
 
+    - name: Add Joe to nonexistant job template execute role
+      role:
+        user: "{{ username }}"
+        role: execute
+        workflow: test-role-workflow
+        job_templates:
+          - non existant temp
+        state: present
+      register: result
+      ignore_errors: true
+
+    - assert:
+        that:
+          - "'There were 1 missing items, missing items' in result.msg"
+          - "'non existant temp' in result.msg"
+
     - name: Add Joe to workflow execute role, no-op
       role:
         user: "{{ username }}"