tui for jj arrange seems to break if your stack is taller than your terminal

[mgaudet]

Description

Steps to Reproduce the Problem

1. Have a stack of commits which render taller than your terminal
2. use jj arrange
3. Try and move the cursor down... notice that you don't scroll, and instead become blind at the bottom

Expected Behavior

TUI follows scroll

Actual Behavior

TUI pinned to top

Specifications

• Platform: macos
• Version: jj 0.39