[Cashtab] Remove legacy walletState parameter

Summary:
T1742

Remove legacy walletState parameter.

walletState was replaced by wallet.state to enable local storage support for utxo set and token balances, speeding up Cashtab.

This was already done in every screen using wallet.state. This diff completes the deprecation of walletState by removing it from useWallet.js (where it was still used for incoming tx notifications)

Test Plan:
npm start
Receive an XEC tx and note tx notification
Receive an eToken tx and note tx notification

Reviewers: #bitcoin_abc, majcosta

Reviewed By: #bitcoin_abc, majcosta

Differential Revision: https://reviews.bitcoinabc.org/D9894