Merge pull request #10589 from AlanCoding/null_traceback

No result_traceback is blank, not null

I kept staring at a failure where:

cannot create resource

was expected in result_traceback, but it was blank. The job had "error" status, sure enough.
Then I re-created, sure enough, the job was right there - error status, no explanation, no traceback, no indication of what happened. We did have logs though (which I still can't fully disambiguate).
After that initial confusion, I realized this is a server-side bug. The test is happy with what happens after this change.
I can re-organize this diff if needed.

Reviewed-by: Elijah DeLee <kdelee@redhat.com>
Reviewed-by: Bianca Henderson <beeankha@gmail.com>
Reviewed-by: Shane McDonald <me@shanemcd.com>

awx/main/tasks.py

@@ -3004,7 +3004,7 @@ class AWXReceptorJob:
                 if state_name == 'Succeeded':
                     return res
 
-                if self.task.instance.result_traceback is None:
+                if not self.task.instance.result_traceback:
                     raise RuntimeError(detail)
 
         return res