[Cashtab] Better error handling for rendering txs

Summary:
Now that we are in in-node chronik, tokenEntries will always be an array. However, some users got this error when Cashtab migrated to in-node chronik, since parsedTxHistory loaded from storage does not have tokenEntries (coming from nng chronik).

Add better validation to handle this migration case.

Test Plan: npm test

Reviewers: #bitcoin_abc, emack

Reviewed By: #bitcoin_abc, emack

Subscribers: emack

Differential Revision: https://reviews.bitcoinabc.org/D15772