[Due for payment 2025-08-05] [Due for payment 2025-07-17] Update mobile test drive modal to have better scroll behavior

[shawnborton]

We want to update the Test Drive modal on mobile to have:

• a max-height so that we still show a bit of the top app bar, and allow the user to tap outside to close
• sit on top of the fixed keyboard
• scroll the content, which will help us in the focused situation

We end up with something like this:

CleanShot.2025-06-05.at.11.34.22.mp4

cc @danielrvidal to help me add labeling/prioritization to this one

cc @jmusial to implement the changes

cc @Expensify/design for viz!

[melvin-bot]

Triggered auto assignment to @Gonals, see https://stackoverflow.com/c/expensify/questions/7972 for more details.

[melvin-bot]

⚠️ Looks like this issue was linked to a Deploy Blocker here

If you are the assigned CME please investigate whether the linked PR caused a regression and leave a comment with the results.

If a regression has occurred and you are the assigned CM follow the instructions here.

If this regression could have been avoided please consider also proposing a recommendation to the PR checklist so that we can avoid it in the future.