handle any non utf8 payloads

just replace unknown utf8 characters to pre preserve the presence of a message

Signed-off-by: Reuben Miller <[email protected]>

tests/RobotFramework/libraries/ThinEdgeIO/ThinEdgeIO.py

@@ -501,8 +501,7 @@ def _assert_mqtt_topic_messages(
         )
 
         messages = [
-            bytes.fromhex(item["payload_hex"]).decode("utf8")
-            # item["message"]["payload"]
+            bytes.fromhex(item["payload_hex"]).decode("utf8", errors="replace")
             for item in items
         ]
 
@@ -525,7 +524,7 @@ def log_mqtt_messages(self, topic: str = "#", date_from: Union[datetime, float]
             **kwargs,
         )
         entries = [
-            f'{item["message"]["tst"].replace("+0000", ""):32} {item["message"]["topic"]:70} {bytes.fromhex(item["payload_hex"]).decode("utf8")}'
+            f'{item["message"]["tst"].replace("+0000", ""):32} {item["message"]["topic"]:70} {bytes.fromhex(item["payload_hex"]).decode("utf8", errors="replace")}'
             for item in items
         ]
         log.info("---- mqtt messages ----\n%s", "\n".join(entries))