Add minimum width/height to dialog buttons

[Calinou]

This makes buttons with short texts such as "OK" or "Close" easier to click, especially on a touchscreen.

This is exposed to projects via buttons_min_width and buttons_min_height theme items in AcceptDialog (and therefore ConfirmationDialog and FileDialog), with the default values being 0 to preserve compatibility with existing projects.

Preview

AcceptDialog

Before

Default	Compact	Spacious

ConfirmationDialog

Before

Default	Compact	Spacious

[passivestar]

Looking good 👍

Unrelated: most dialog windows in godot are missing paddings

[Calinou]

Unrelated: most dialog windows in godot are missing paddings

See #89718.

[kleonc]

This doesn't play well with the interface/theme/spacing_preset editor setting (added in #87085). At least for the "Compact" preset it feels to not fit in.

[Calinou]

This doesn't play well with the interface/theme/spacing_preset editor setting (added in #87085). At least for the "Compact" preset it feels to not fit in.

I've pushed an update that adjusts padding based on the spacing preset. Spacing with the Default preset was also reduced by a few pixels on both axes. See OP for updated screenshots.

[kleonc]

I've pushed an update that adjusts padding based on the spacing preset. Spacing with the Default preset was also reduced by a few pixels on both axes. See OP for updated screenshots.

Way better now!
To me they still look big in the "Compact" preset but I guess that's the point of this PR. So should be fine as is. 🙂

You also need to add docs for the added theme properties.

[Calinou]

You also need to add docs for the added theme properties.

Done.

[akien-mga]

Thanks!