More informative error handling

[dchiquito]

If the authorizationServerBaseUrl argument passed to OauthClient is not a complete URL, no exception will be thrown until the openid RedirectRequestHandler attempts to build a new URL(...) object out of it. Sadly, the error is swallowed by this try/catch:

girder-oauth-client/src/oauth-client.ts

Lines 45 to 51 in 36bbcbe

	try {
	this.token = await this.oauthFacade.finishLogin();
	} catch {
	// Most likely, there is no pending Authorization flow.
	// Possibly, there is an Authorization failure, which will be emitted to the
	// console, but doesn't need to be fatal, since this can just proceed with no token.
	}

Either an earlier check for this malformed user input or a more specific catch would have saved me a few hours of debugging.