[marlin] Add lots of end to end send tests

Summary:
The send screen from marlin has many features that need to be tested, from slider input to transaction details and paybutton handling. This diff adds a bunch of end to end tests for this screen. The test title should be enough to understant the intent.

Depends on D19819.

Test Plan:

pnpm run test:e2e

Reviewers: #bitcoin_abc, PiRK

Reviewed By: #bitcoin_abc, PiRK

Differential Revision: https://reviews.bitcoinabc.org/D19820