To fix error while using update_config script

@ahmedk

There was at somepoint an issue with MID when Ulrike was trying to update (create as it was first time) the config file (https://git.xfel.eu/gitlab/detectors/calibration_configurations/blob/master/202022/002693.yaml) using update_config script.

It generated erroneous yaml file where data-mapping section also has MID as a key however it should be karabo_id instead of MID. This issue will occur if the yaml file is generated first time from default.

webservice/webservice.py

@@ -176,7 +176,7 @@ async def change_config(socket, config, updated_config, karabo_id, instrument, c
                 if action != "data-mapping":
                     subconf[action][instrument] = instruments[instrument]
                 else:
-                    subconf[action][instrument] = instruments[karabo_id]
+                    subconf[action][karabo_id] = instruments[karabo_id]
             with open(fpath, "w") as wf:
                 wf.write(yaml.dump(subconf, default_flow_style=False))
     new_conf = None