fix(Icon Button): Draw the contrast hover background from the text colour

[VincentSmedinga]

Describe the pull request

Links

• Storybook for this branch
• Icon Button, contrast colour

What

Change the background of a hovered contrast Icon Button from rgb(0 0 0 / 12.5%) to rgb(32 32 32 / 12.5%).

Why

The 12.5% transparency must be drawn from the text colour, #202020, not from pure black.

How

A token cannot apply an alpha to another token, so the value is a literal, like the hover background of the default Icon Button.
This was the only pure black in the default theme's tokens.
We probably did not find it earlier because it is written as rgb() with an alpha, while every other colour is a hex value.

Checklist

Before submitting your pull request, please ensure you have done the following. Check each checkmark if you have done so or if it wasn't necessary:

• Add or update unit tests
• Add or update documentation
• Add or update stories
• Add or update exports in index.* files
• Comment /chromatic test and verify visual regression tests pass
• Start the PR title with a Conventional Commit prefix, as explained here.

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[github-actions]

Coverage Report for React components

Status	Category	Percentage	Covered / Total
🟢	Lines	100%	1181 / 1181
🟢	Statements	100%	1254 / 1254
🟢	Functions	100%	315 / 315
🟢	Branches	100%	917 / 917

File Coverage

No changed files found.

Generated in workflow #681 for commit 1a5f8e3 by the Vitest Coverage Report Action

[github-actions]

Size Change: +2 B (0%)

Total Size: 428 kB

📦 View Changed

Filename	Size	Change
packages-proprietary/tokens/dist/index.css	11.6 kB	+2 B (+0.02%)

ℹ️ View Unchanged

Filename	Size
packages-proprietary/react-icons/dist/index.esm.js	55.5 kB
packages-proprietary/temp/assets-fonts.tar.gz	168 kB
packages-proprietary/temp/assets-others.tar.gz	120 kB
packages-proprietary/tokens/dist/compact.css	600 B
packages-proprietary/tokens/dist/lo-fi.css	1.56 kB
packages/css/dist/index.css	18.1 kB
packages/react/dist/index.esm.js	50.9 kB
packages/react/dist/index.js	499 B

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