attempt to divide by zero when resizing the terminal

[diegostafa]

Summary

similarly to #1403, the program crashes when resizing the terminal while the preview/info box is displayed
see the reproduction steps below

Reproduction Steps

I tried this:

1. open a terminal
2. run helix
3. press colon to open the prompt
4. press tab to show the preview/info box above the items
5. make the terminal really small (0 x 0)

I expected this to happen:

• helix resizes accordingly

Instead, this happened:

• helix crashed

Helix log

thread 'main' panicked at helix-term/src/ui/prompt.rs:404:34:
attempt to divide by zero

Platform

arch linux

Terminal Emulator

alacritty

Installation Method

pacman

Helix Version

helix 23.10