fix(Tabs): Ensure Button to be the target of pointer events

[VincentSmedinga]

Describe the pull request

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What

Disallows children of a Tabs.Button to become the target of pointer events.

Why

To ensure the click event always returns the button as its target.

How

Through CSS.

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
• Start the PR title with a Conventional Commit prefix, as explained here.

Additional notes

• Adresses V0.14.0 Inconsistent MouseEvent Target in Tabs Component #1846.
• We can release this as a 0.14.1 hotfix.
• I considered adding a Storybook interaction test, but decided against it to keep the bugfix minimal. We should make a start with the subject, though.
• Test this by adding onClick: (e: MouseEvent<HTMLElement>) => console.log('e.target:', e.target) to the args of the Tabs stories while importing MouseEvent from React.