Fix httpClient should not throw if user is disconnected

[slax57]

Problem

If the token cannot be acquired from the cache (e.g. because it is no longer valid or because the user is disconnected), calling auth0Client.getTokenSilently() in httpClient will throw an Error (e.g. a Login required error).

The problem is that this will block the actual request from firing, and it will not necessarily trigger a new login attempt since authProvider.checkError() won't throw in that case.

Solution

Catch any error thrown while calling auth0Client.getTokenSilently() in httpClient, and rely on the fact that the API will then be called without the Authorization header, which should return a 401 or 403 status code (if the endpoint is protected) which should activate authProvider.checkError().