Error Handling Improvement for connection to LND/Wallets Service

[lc0des]

I have spent a real amount of time getting things to work in my personal setup. I think that an improved
error handling in lnbits can spare other people a lot of time. Examplary i will focus only on the Wallet
Connection as this was one major points i struggeled with.
When lnbits is started the method check_funding_source is called. In there the function check_wallet_status. This function receives an error message if something is going wrong.

def check_funding_source(app: QuartTrio) -> None:
    @app.before_serving
    async def check_wallet_status():
        error_message, balance = await WALLET.status()
        if error_message:
            warnings.warn(
                f"  × The backend for {WALLET.__class__.__name__} isn't working properly: '{error_message}'",
                RuntimeWarning,
            )

However, it is not stating what exactly is going wrong, as can be seen here:

    async def status(self) -> StatusResponse:
        try:
            async with httpx.AsyncClient(verify=self.cert) as client:
                r = await client.get(
                    f"{self.endpoint}/v1/balance/channels",
                    headers=self.auth,
                )
        except (httpx.ConnectError, httpx.RequestError):
            return StatusResponse(f"Unable to connect to {self.endpoint}.", 0)

        try:
            data = r.json()
            if r.is_error:
                raise Exception
        except Exception:
            return StatusResponse(r.text[:200], 0)

        return StatusResponse(None, int(data["balance"]) * 1000)

The exception catches (httpx.ConnectError, httpx.RequestError) but is not catching the error itself, like
for instance unauthorized, wrong ssl certificated, connection refused, connection timeout to name just a few: currently the code only returns:
return StatusResponse(f"Unable to connect to {self.endpoint}.", 0)

As a result it makes a hard time for someone trying to debug the issue.

Better:
Grab also the error created from the httpx library and return it at least in the daemon print area or better
in a debug logfile.

[dni]

merged