beginning with release 135, regular release cycle Firefox for Linux installers are now using xz instead of bz2

[jsvnsk]

beginning with Firefox for Linux release 135, the regular release cycle Firefox for Linux installers have transitioned from using .tar.bz2 to .tar.xz for the packaging format

this change was announced for the nightly release installers back in November in the following blog posting:
https://blog.nightly.mozilla.org/2024/11/28/announcing-faster-lighter-firefox-downloads-for-linux-wi... 

legacy example URL (bz2 format):
https://download-installer.cdn.mozilla.net/pub/firefox/releases/134.0/linux-x86_64/en-US/firefox-134... 

new example URL (xz format):
https://download-installer.cdn.mozilla.net/pub/firefox/releases/135.0/linux-x86_64/en-US/firefox-135...