Invalid public_baseurl in homeserver causes app to sync forever

If you configure your homeserver to send an invalid homeserver URL (the `public_baseurl` config in synapse: in my case set to 'localhost' ie. valid, but not accepting connections) the app will log in and then stay on the syncing spinner forever. It should probably just error & go back to the login screen. Killing the app seemed to go back into the same state, so I had to uninstall element to get out of it.

Android has the same bug: https://github.com/vector-im/element-android/issues/3472