[Cashtab] [wallet mgmt improvements p6] Rename wallet param to activeWallet in renameActiveWallet

Summary:
T2822

Depends on D12846

The use of wallet as a param here is ambiguous as wallet is also an important state variable in useWallet.js

Use activeWallet instead

Test Plan:
Confirm that every instance of wallet is replaced with activeWallet in renameActiveWallet, although the string key 'wallet' should be unchanged as this is where we are saving in local storage
npm start
Rename an active wallet
Rename is effective

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D12847