[Cashtab] Deprecate biometric authentication

Summary:
T2881

Deprecate biometric authentication. The feature does not persist through Cashtab state change (i.e. a hard refresh). The feature would be technically complex to support through local storage, which is also not 100% reliable in a web app as it depends on the browser.

These gaps make the feature more a security threat vector than a security feature. It is only able to lock the app using the same lock a user has set on their phone. This redundant lock (that sometimes disables itself) should be deprecated.

Test Plan:
npm start
App works fine
Settings page does not display lock setting
npm run build
netlify deploy
Test on mobile with app that was previously set to auth on -- should load with auth off, no issues
Test on mobile with app that was previously set to auth off -- should load with auth off, no issues

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D12899