Improve UI of proceed sheet

Right now if the text is really long, it gets elided at the bottom so you need to click a button to see the rest, and the two distinct sections of the text are kind of unclear.

This commit puts the text in the sheet's own scrollview so you can scroll immediately, and adds a line break between the sections. It also puts the bottom buttons in a footer, which looks better.

Before:

After:

cc @teams/vdg