[Cashtab] Remove obsolete cache dependencies

Summary:
These were added in an early alias implementation diff that used cache for alias features. We stopped doing this but forgot to remove the dependencies. git blame is D13367

Remove the now-unused cashtabCache uses

Test Plan: npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Differential Revision: https://reviews.bitcoinabc.org/D15572