Revert "Revert "[Cashtab] Convert wallet context to ts""
Summary:
This reverts commit b88a433009eaca5a4fcb685f7a611665f115881b.
Identified and resolved the bug that caused this to fail builds in prod. Was an issue with not properly initWasm()
See updated file cashtab/src/index.tsx and the much lighter lint-related changes that are applied here vs in the original diff.
Test Plan:
npm test
npm start and app loads
npm run build and app builds
Reviewers: #bitcoin_abc, emack
Reviewed By: #bitcoin_abc, emack
Differential Revision: https://reviews.bitcoinabc.org/D17311