Prevent panels from getting so small they can't be resized (#3788)

This also switches to using `Pixels` instead of `f32` to store the panel
size everywhere.

Release Notes:

- N/A
30340535e9Antonio Scandurra committed on 12/22/2023, 5:37:13 PM· committed by GitHubparents25a5eda961d833
12 files changedLine totals unavailable