Fix return of no alerts failing

Author: kzscisoft

simvue/factory/proxy/remote.py

@@ -339,8 +339,8 @@ def list_alerts(self) -> list[dict[str, typing.Any]]:
             self._error(f"Got exception when listing alerts: {str(err)}")
             return []
 
-        if not (response_data := response.json()) or not (
-            data := response_data.get("data")
+        if not (response_data := response.json()) or (
+            (data := response_data.get("data")) is None
         ):
             self._error(
                 "Expected key 'data' in response from server during alert retrieval"