Transaction error: make more informative

Ideally prevent this error. It shows up randomly and could happen for a number of reasons.

1. We need to give better info to users so that they can recover from this error and proceed to complete their task. E.g.,

> “Transaction error, something went wrong. Please login and try again”

2. We should better handle how we report these errors to Sentry to help us debug.


The issue names no files, tests, or entry points. Trace where transaction failures are surfaced in the mobile app and reported to Sentry; done means users receive actionable error information and Sentry receives better diagnostic context.

Written by the indexing model from the issue text.