fix(theme-classic): minor code copy button improvements

[Josh-Cena]

Motivation

• Reduced the timeout to 1s which seems more sensible
• Clean up the timeout before unmount because state is mutated in the timeout:

I also think that the button is only ever reset to the original state after the timeout, so even when the cursor leaves the code block, the button stays as a tick, which seems a little weird. But changing that requires moving state management up to CodeBlock which seems too much trouble.

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

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✅ [V2]

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[Josh-Cena]

Ugh, the GitHub actions never kicked 😄

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🔴 Performance	47
🟢 Accessibility	100
🟢 Best practices	92
🟢 SEO	100
🟢 PWA	90

Lighthouse ran on https://deploy-preview-6986--docusaurus-2.netlify.app/

[github-actions]

Size Change: 0 B

Total Size: 806 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	49.9 kB
website/build/assets/css/styles.********.css	105 kB
website/build/assets/js/main.********.js	612 kB
website/build/index.html	38.8 kB

_{compressed-size-action}

[slorber]

👍

I also think that the button is only ever reset to the original state after the timeout, so even when the cursor leaves the code block, the button stays as a tick, which seems a little weird. But changing that requires moving state management up to CodeBlock which seems too much trouble.

Note that technically we already have CopyButton CSS targeting a parent (but stable global) CSS selector so we could do the same with JS and attach a mouseOut listener

Not sure it's worth it though so I'll merge this as is