Catch error when actinia-core is not reachable

[mmacata]

Currently when starting a job and actinia-core is not responsive or the request is unauthorized, {"message": "Internal Server Error"} is returned with the logs showing an exception

  File "/src/actinia-cloudevent-plugin/src/actinia_cloudevent_plugin/core/cloudevents.py", line 87, in start_actinia_job
    return json.loads(resp.text)

and actinia-core logs showing e.g.

[2026-03-06 09:56:35,645] INFO      : gunicorn.access.glogging   -10.42.7.105 - actinia-gdi [06/Mar/2026:09:56:35 +0000] "POST /api/v3/projects/nc_spm_08/processing_export HTTP/1.1" 401 19 "-" "python-requests/2.32.5" [in /opt/venv/lib/python3.12/site-packages/gunicorn/glogging.py:362]

This error can be catched and the message adjusted accordingly.