[Connector] add method to get connected wallet checksum

[arobsn]

Exposing the wallet's name (as chosen by the user) can be considered a privacy violation in some cases, so exposing wallet's CIP-4 checksum sounds more appropriate here.

get_wallet_checksum(): { text: string, image: HexString }

[c8e4]

As a user i never pay attention to those. Maybe it's time to introduce permissions? A dapp can reqest wallet name in the same screen as wallet selection.
Additional permissions like wallet name are checkboxes that can be explicitly checked! <- default unchecked