[Cashtab] Improve isValidContactList function and tests

Summary:
Wallets with aliases in contact list currently throw the list out and do not set to context. Patch this.

Migrate legacy tests to vectors to improve readability. Add new vector for alias case.

Test Plan: npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D15347