push_diff_attach_model: run payload thru json.dumps()

1. plugins/module_utils/vrf/dcnm_vrf_v12.py

-  push_diff_attach_model

Getting a different 500 error with latest changes.  Let’s try running the model-generated payload through json.dumps().  The payload looks fine to me, but includes only single backslash escape characters rather than triple-backslash. Maybe json.dumps() will fix this.  If so, will look into the model’s field_serializer for a proper solution.

Author: allenrobel

plugins/module_utils/vrf/dcnm_vrf_v12.py

@@ -3629,7 +3629,7 @@ def push_diff_attach_model(self, is_rollback=False) -> None:
             action="attach",
             path=f"{endpoint.path}/attachments",
             verb=endpoint.verb,
-            payload=payload,
+            payload=json.dumps(payload) if payload else payload,
             log_response=True,
             is_rollback=is_rollback,
         )