NVD uses "aomedia" as the vendor for libavif CVEs. This change adds
libavif to the APK package CPE candidate additions with "aomedia" as
an additional vendor, enabling Syft/Grype to match CVEs like
CVE-2025-48174 and CVE-2025-48175.
Signed-off-by: Peter Bücker <peter.buecker@gmail.com>