Implement recursive spawned job cancel.

awx/api/views.py

@@ -2869,6 +2869,14 @@ class WorkflowJobCancel(RetrieveAPIView):
     is_job_cancel = True
     new_in_310 = True
 
+    def post(self, request, *args, **kwargs):
+        obj = self.get_object()
+        if obj.can_cancel:
+            obj.cancel()
+            return Response(status=status.HTTP_202_ACCEPTED)
+        else:
+            return self.http_method_not_allowed(request, *args, **kwargs)
+
 class SystemJobTemplateList(ListAPIView):
 
     model = SystemJobTemplate