feat!: Replace ‘on background’ props with ‘inverseColor’ and ‘contrastColor’ for Link, Link List Link, and Icon Button

[VincentSmedinga]

Describe the pull request

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What

This replaces onBackground="light" with contrastColor={true} and onBackground="dark" with inverseColor={true} for Link, Link List Link, and Icon Button. Related tokens and class names are affected.

Why

We had an inconsistency between this onBackground prop and the inverseColor prop of many other components. We’ve analyzed that and found that adding a constrastColor prop allows us to use the inverseColor prop consistently.

Shortly, the ‘contrast color’ is an alternative foreground colour for a text or icon component if they are on a light (not white) background. The ‘inverse color’ is the same for a dark background.

How

This is largely a ‘find and replace’ refactoring.

I chose not to add visited colours to these components, even thought the tokens for it are available in the link-appearance layer.

Checklist

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