[Cashtab][Alias] Deprecate appendWithPendingAliases

Summary: appendWithPendingAliases is no longer in use as the prod alias-server instance no longer has a pending endpoint.

Test Plan:
npm test
npm start and sanity check cashtab with the alias flag off

Reviewers: bytesofman, #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14236