www/waterfox: Update 6.7.1.1 => 6.7.3

Release Notes:
https://www.waterfox.com/releases/6.7.2/
https://www.waterfox.com/releases/6.7.3/

Changelog:
https://github.com/BrowserWorks/waterfox/releases/tag/6.7.2
https://github.com/BrowserWorks/waterfox/releases/tag/6.7.3

PR: 298443
Approved by: Martin Filla <freebsd@sysctl.cz> (maintainer)
MFH: 2026Q3