Fix start_scan() and get_scan_status()

[atj]

The startScan and getScanStatus endpoints return a subsonic-response with a nested scanStatus element on success.

https://opensubsonic.netlify.app/docs/endpoints/startscan/
https://opensubsonic.netlify.app/docs/endpoints/getscanstatus/

Whilst testing calling startScan on my LMS server I encountered the following error:

Traceback (most recent call last):
  File "/home/atj/dev/opensubsonic/test.py", line 47, in <module>
    conn.start_scan()
    ~~~~~~~~~~~~~~~^^
  File "/home/atj/dev/venv/lib/python3.13/site-packages/libopensonic/_sync/connection.py", line 2064, in start_scan
    return ScanStatus.from_dict(dres['scanstatus'])
                                ~~~~^^^^^^^^^^^^^^
KeyError: 'scanstatus'

Further investigation showed that the response contained a scanStatus element but the code was checking for scanstatus. Here's an example response from LMS:

<Response [200]>
{'openSubsonic': True,
 'scanStatus': {'scanning': False},
 'serverVersion': 'v3.76.0',
 'status': 'ok',
 'type': 'lms',
 'version': '1.16.1'}

[khers]

Looks good and sorry for the delay!