Allow deleting org of a running workflow job (#15374)

Old RBAC system hits DOESNOTEXIST query errors
if a user deletes an org while a workflow job is active.

The error is triggered by
1. starting workflow job
2. delete the org that the workflow job is a part of
3. The workflow changes status (e.g. pending to waiting)

This error message would surface
awx.main.models.rbac.Role.DoesNotExist: Role matching
query does not exist.

The fix is wrap the query in a try catch, and skip
over some logic if the roles don't exist.

---------

Signed-off-by: Seth Foster <fosterbseth@gmail.com>

awx/main/models/rbac.py

@@ -689,9 +689,15 @@ def sync_parents_to_new_rbac(instance, action, model, pk_set, reverse, **kwargs)
 
     for role_id in pk_set:
         if reverse:
-            child_role = Role.objects.get(id=role_id)
+            try:
+                child_role = Role.objects.get(id=role_id)
+            except Role.DoesNotExist:
+                continue
         else:
-            parent_role = Role.objects.get(id=role_id)
+            try:
+                parent_role = Role.objects.get(id=role_id)
+            except Role.DoesNotExist:
+                continue
 
         # To a fault, we want to avoid running this if triggered from implicit_parents management
         # we only want to do anything if we know for sure this is a non-implicit team role