Prepare switch to mozilla83 for mobile

This is the parent ticket for organizing all the work we need to do before releasing Tor Browser for Android based on Fenix 83.x.

• tor-browser-bundle-testsuite#40009 (closed)
• android-components#40018 (closed)
• fenix#40080 (closed)
• fenix#40081 (closed)
• tor-browser-build#40126 (closed)
• tor-browser-build#40127 (closed)
• #40187 (closed)
• #40188 (closed)
• #40189 (closed)
• #40190 (closed)
• #40215 (closed)
• tor-browser-spec#40006 (closed)
• #40233 (closed)
• fenix#40113 (closed)
• android-components#40026 (closed)