4.34.15 - Manifest V3 proxy extension

Manifest V3 proxy extension

• Update proxy extension for Manifest V3 compatibility
  --> This resolves #3517
  --> This extension is needed for authenticated proxy
• Refactor browser_launcher.py
• Update the proxy test

What's Changed

• Manifest V3 proxy extension by @mdmintz in #3519

Full Changelog: v4.34.14...v4.34.15