[Cashtab] Improve performance of flaky test by waiting for async text to appear

Summary: Seeing this step fail (at least once) in CI. Change query params to async wait for this component to appear when expected.

Test Plan: npm test

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D18045