Change styling of sortissues dropdown

[isaiahaquino]

PR 🚀

🛠 Proposed Changes

Original dropdown does not look consistent with the theme of the site.

🖼️ Screenshots

Checklist ✅

• [ x] Starred this repo ⭐.
• [ x] Code adheres to the project's coding standards 💻.
• [ x] No sensitive information is inadvertently exposed 👀.
• [ x] Commit history is clear and concise 📃.