[Cashtab] Remove async useEffect methods

Summary:
React 18 does not support async useEffect blocks. In prep to upgrade to React 18, refactor these blocks so that we are not awaiting withing useEffect

Note: we can still achieve the same functionality. This is a syntax issue.

Test Plan: Confirm new functions contain exact content of old useEffect blocks. npm test

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D15341