[Cashtab] [bch-api deprecation p1]Remove bch-api node check from useWallet.js

Summary:
T2730

Remove bch-api server check from update function in useWallet.js

Now that bch-api is no longer used for utxo mgmt, tx history, or broadcasting txs, there is no point in checking on the server. It doesn't matter if it's up or down, Cashtab is not using it.

Test Plan: npm start and wallet just works

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D12366