[Cashtab] Click anywhere to close the tx success modal

Summary: Feedback that it is annoying to have to move the mouse and close this. Will also add a setting so that we can still have it autoclose. For now tho, support clicking anywhere to close.

Test Plan: npm test, i tested by deploying to cashtab.io and opening with a webapp, clicking anywhere, closes the window

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D18550