Qt: Make General->Debug scrollable

Configuration -> General -> Debug is getting a bit crowded.

yzct12345 submit this originally, so I'm tagging them as a co-author.
The original #6714 also modifies the Controls -> Player N sections,
but it looks like more work is needed to make the current area scrollable.

Co-authored-by: yzct12345 <87620833+yzct12345@users.noreply.github.com>