Prevent "failed to convert null" qt warning

src/python/matrix_client.py

@@ -458,8 +458,8 @@ class MatrixClient(nio.AsyncClient):
     ) -> str:
 
         response = await super().room_create(
-            name       = name,
-            topic      = topic,
+            name       = name or None,
+            topic      = topic or None,
             federate   = federate,
             visibility =
                 nio.RoomVisibility.public if public else

src/qml/Pages/AddChat/CreateRoom.qml

@@ -20,8 +20,8 @@ HBox {
             errorMessage.text = ""
 
             let args = [
-                nameField.text || null,
-                topicField.text || null,
+                nameField.text,
+                topicField.text,
                 publicCheckBox.checked,
                 encryptCheckBox.checked,
                 ! blockOtherServersCheckBox.checked,