scanner fails badly when backend is unavailable

Kyoo's version

^HEAD
What happened?

When backend is down / unreachable then scanner fails instead of somehow handle such situation:
❯ ~/homelab k logs kyoo-scanner-5544899798-pzjll -n media
INFO:scanner.scanner:Starting the scan. It can take some times...
Traceback (most recent call last):
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 1073, in _wrap_create_connection
    sock = await aiohappyeyeballs.start_connection(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohappyeyeballs/impl.py", line 104, in start_connection
    raise first_exception
  File "/usr/local/lib/python3.12/site-packages/aiohappyeyeballs/impl.py", line 81, in start_connection
    sock = await _connect_sock(
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohappyeyeballs/impl.py", line 166, in _connect_sock
    await loop.sock_connect(sock, address)
  File "/usr/local/lib/python3.12/asyncio/selector_events.py", line 651, in sock_connect
    return await fut
           ^^^^^^^^^
  File "/usr/local/lib/python3.12/asyncio/selector_events.py", line 659, in _sock_connect
    sock.connect(address)
PermissionError: [Errno 1] Operation not permitted

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/app/scanner/__main__.py", line 6, in <module>
    asyncio.run(scanner.main())
  File "/usr/local/lib/python3.12/asyncio/runners.py", line 194, in run
    return runner.run(main)
           ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/asyncio/runners.py", line 118, in run
    return self._loop.run_until_complete(task)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/asyncio/base_events.py", line 687, in run_until_complete
    return future.result()
           ^^^^^^^^^^^^^^^
  File "/app/scanner/__init__.py", line 20, in main
    await asyncio.gather(
  File "/app/scanner/__init__.py", line 18, in scan_all
    await scan(path, publisher, client, remove_deleted=True)
  File "/app/scanner/scanner.py", line 32, in scan
    registered = await client.get_registered_paths()
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/app/providers/kyoo_client.py", line 42, in get_registered_paths
    async with self.client.get(
               ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/client.py", line 1353, in __aenter__
    self._resp = await self._coro
                 ^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/client.py", line 657, in _request
    conn = await self._connector.connect(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 564, in connect
    proto = await self._create_connection(req, traces, timeout)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 975, in _create_connection
    _, proto = await self._create_direct_connection(req, traces, timeout)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 1350, in _create_direct_connection
    raise last_exc
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 1319, in _create_direct_connection
    transp, proto = await self._wrap_create_connection(
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.12/site-packages/aiohttp/connector.py", line 1088, in _wrap_create_connection
    raise client_error(req.connection_key, exc) from exc
aiohttp.client_exceptions.ClientConnectorError: Cannot connect to host kyoo-back:5000 ssl:default [Operation not permitted]
zoriya / Kyoo

scanner fails badly when backend is unavailable #646

Kyoo's version

What happened?
