Review Firefox 138 Developer + Release Notes

We should read over the notes put out by Mozilla and open any further audit issues if necessary.

Developer Notes

• https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/138

Release Note:

• 138.0: https://www.mozilla.org/en-US/firefox/138.0/releasenotes/
• 138.0.1: https://www.mozilla.org/en-US/firefox/138.0.1/releasenotes/