Upgrade to use-wallet v3

[neilcampbell]

We use some interesting tricks in lora to support network switching in use-wallet v2, so we might be able to simplify the integration. It will need to be throughly tested after upgrade though.

In v2 the KMD provider doesn't store the active KMD wallet, so when reloading it assumes unencrypted-default-wallet. If you connect a different wallet, then reload transaction signing breaks. To fix this we disconnect the KMD wallet on reload. Hopefully v3 has fixed this, so we can remove this behaviour, as it's annoying.