[Cashtab][Alias] Deprecate getAddressFromAlias

Summary:
T3216

Following on from refactors in D14211, D14212 and D14266, getAddressFromAlias is no longer in use.

Test Plan:
grep -r getAddressFromAlias src/
npm test

Reviewers: bytesofman, #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14322