WIP: Refactor button styling

[jamesmockett]

What are you changing?

• Removes CSS overrides for icon / spinner size and colour in favour of size and theme prop
• Removes isLoading and loadingAnnouncement props from LinkButton as these are unsupported
• Refactors styles to simplify and remove duplication

Why?

• Using props rather than CSS overrides makes styling more predictable
• Simplifying the styles makes things easier to understand and update

To do

• Replace spacer <div>

[changeset-bot]

⚠️ No Changeset found

Latest commit: fa45364

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[github-actions]

Tip

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[github-actions]

"This PR was marked stale because it has been open for 30 days without activity. If nothing happens, it will be closed 3 days from now."

[github-actions]

This PR was closed because nothing happened for 3 days after becoming stale.