ToggleGroupControl: Update large button size to 32px

[mirka]

Closes #45532

What?

Updates the size of the ToggleGroupControl buttons in the large size variant to be 32px (used to be 34px).

Also fixes a bug where icon buttons did not have square proportions when size = 'default' && __next40pxDefaultSize = true.

Why?

As requested, to be more cohesive with the overall sizing scheme.

Testing Instructions

In the Storybook stories for ToggleGroupControl, see that the button sizes for size = '__unstable-large' and __next40pxDefaultSize = true are now 32px. Check both the text label buttons and icon buttons.

The overall footprint (height) including the border around the entire button group should remain the same at 40px.

Screenshots or screencast

Bug fix for icon buttons where size = 'default' && __next40pxDefaultSize = true:

Before	After

[mirka]

We usually don't do this kind of preemptive size normalization in other components, but in this specific case it was a lot cleaner this way. Otherwise we'd have to drill the prop down to multiple subcomponents, touching a handful of more files.

[ciampo]

Agreed. We should be able to clean this up after the migration is over and we remove temporary props and size values

[mirka]

I am tempted to simplify this down to a

if ( size === 'default` ) {
  return css`/* ... */`;
}
return css`/* ... */`;

but I'm going to keep this size variant object around because I think we'll be asked to make a 32px compact size variant soon.

[github-actions]

Flaky tests detected in a803192.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/7321454753
📝 Reported issues:

• [Flaky Test] Should show Columns block only if selected blocks are between limits (1-6) #40369 in specs/editor/various/block-switcher.test.js

[ciampo]

🚀

Tests well as per instructions

[ciampo]

Agreed. We should be able to clean this up after the migration is over and we remove temporary props and size values