[Cashtab] Simplify and standardize Configure integration tests

Summary:
Cashtab integration tests exist, which is good. But they are bloated, and usually exhibit artifacts of the iterative / discovery process of writing them.

Continue optimizing and standardizing Cashtab integration tests by implementing the same component type used for the App integration tests, which is the same type used by the prod app in index.js.

Apply best practices to simplify test. Instead of repeating most of the same steps (render the app, open the collapse) -- combine into one integration test that demonstrates the same behavior.

Test Plan: npm test

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D15464