fix(youtube): improve button styling

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🔧 What does this fix? 🔧

Makes buttons like the two here look better by adding a different background on hover and matching the hover background of the outline button more closely to YouTube's own styling:

🗒 Checklist 🗒

• [x] I have read and followed Catppuccin's contributing guidelines.
• [x] I have updated the version appropriately in the ==UserStyle== header of the catppuccin.user.css file.