firefox: Update user.js to Firefox 99
firefox: Update user.js to Firefox 99

Changes:
- Remove deprecated preferences.
- Enable ETP Strict Mode by default.
- Enable CRLite.
- Enforce secure renegotiation.
- Disable search suggestions in address bar.
- Hide downloads panel.
- Hide What's New toolbar icon.
- Follow OS's reduced motion settings.

jmlntw/dotfiles,jmlntw/dotfiles