select files during commit process

@mpetojevic looks good, but I have two issues in the branch:

When I access a submission, which has a manualgrade folder (aka I already pulled the submission), I receive the following error: Cannot read properties of undefined (reading 'id') Relevant Jupyterhub logs:

    Traceback (most recent call last):
      File "/home/fjaeger/miniconda3/envs/migration/lib/python3.10/site-packages/tornado/web.py", line 1786, in _execute
        result = await result
      File "/home/fjaeger/miniconda3/envs/migration/lib/python3.10/site-packages/jupyter_server/services/contents/handlers.py", line 121, in get
        model = await ensure_async(
      File "/home/fjaeger/miniconda3/envs/migration/lib/python3.10/site-packages/jupyter_core/utils/__init__.py", line 182, in ensure_async
        result = await obj
      File "/home/fjaeger/miniconda3/envs/migration/lib/python3.10/site-packages/jupyter_server/services/contents/filemanager.py", line 877, in get
        raise web.HTTPError(404, "No such file or directory: %s" % path)
    tornado.web.HTTPError: HTTP 404: Not Found (No such file or directory: lectures/lect1/manualgrade/5/31)

My versions:

grader-service                    0.4.1
jupyterhub                        4.0.2
jupyterlab                        4.0.10

The info dialog title for the commit feature is not representative and the last sentence is missing a dot:

TU-Wien-dataLAB / Grader-Labextension

select files during commit process #41