Electrum client stops listening when OS sleeps

[nkuba]

When waiting on an event (e.g. transaction confirmation) in an electrum client from WebSocket connection to electrum server if the OS goes to sleep the WS connection is not reconnected.

[Shadowfiend]

Thanks to URL state management, this is now fixable with a simple page reload.

That said, we should probably just notice when the connection closes and reopen it with exponential backoff if it wasn't closed via API.