[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