Add copy button to code dialog

[compulim]

Changelog Entry

Added

• Added copy button to view code dialog, in PR #5336, by @compulim

Description

Added "Copy code" button to the view code dialog.

Also fixed the dialog width issues.

In short future, we should have Markdown codeblocks rendered in Shiki and the "Copy code" button should go natively in that Shiki-powered component.

Design

Specific Changes

• Updated view code button to show a dialog with "Copy code" button

• I have added tests and executed them locally
• I have updated CHANGELOG.md
• I have updated documentation

Review Checklist

This section is for contributors to review your work.

• Accessibility reviewed (tab order, content readability, alt text, color contrast)
• Browser and platform compatibilities reviewed
• CSS styles reviewed (minimal rules, no z-index)
• Documents reviewed (docs, samples, live demo)
• Internationalization reviewed (strings, unit formatting)
• package.json and package-lock.json reviewed
• Security reviewed (no data URIs, check for nonce leak)
• Tests reviewed (coverage, legitimacy)