CI: Remove FreeBSD 14.3 for devel, and replace macOS 15.3 with 26.3 (#11631)
* Replace FreeBSD 14.3 with 14.4, and macOS 15.3 with 26.3.
* FreeBSD 14.4 seems to have the same problem as FreeBSD 15.0, disabling for now.
(cherry picked from commit b4336659f6)
Co-authored-by: Felix Fontein <felix@fontein.de>