🎨 Palette: Add animation and accessibility to Copy Report button

[emkey1]

💡 What: Added a smooth animation, a checkmark icon, and dynamic accessibility labels to the "Copy Report" button in App Diagnostics.
🎯 Why: To provide better visual and VoiceOver feedback for transient actions, following established patterns.
♿ Accessibility: Added dynamic accessibilityLabel and accessibilityHint to confirm the copy action to screen readers.

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PR created automatically by Jules for task 17878648685630801598 started by @emkey1

[google-labs-jules]

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