[6.x] Comboxbox can be squished when near viewport edge

[martyf]

Bug description

Following on from #13211, when a Combobox has its options appearing near the edge of the viewport, the dropdown now gets incredibly small - so small that you can't actually see any of the options within.

In this screenshot, the "line" is the viewport edge.

If you scroll the window down further, the dropdown will then jump to the top of the field - as expected.

Can the cutoff for when the dropdown goes from below the element to above be adjusted to avoid these too-short drop-down?

How to reproduce

Statamic Alpha 19

Logs

Environment

Statamic Alpha 19

Installation

Fresh statamic/statamic site via CLI

Additional details

No response