Individual settings for proxy and direct receives no longer make sense

[ekzyis]

Since the lightning address now only works when you have a wallet attached, we no longer need both settings. We will always create an invoice from the external wallet, the only setting is if we should try to proxy and maybe if we should fallback to direct receives in case the proxy failed.

However, not sure if a fallback makes sense since the lightning address will always be paid via QR codes afaict and thus there's no fallback once we generated the invoice. The fallback would only make sense for cases where we failed to wrap the invoice.