libvpx: update to 1.16.0

libvpx: update to 1.16.0

Update libvpx to v1.16.0 "Xenonetta Duck". Highlights include:
- Arm SVE2 and Neon optimizations for 12-tap filters.
- AVX512 implementations for Sum of Absolute Differences (SAD).
- Support for per-frame and per-spatial-layer PSNR calculation.
- ABI incompatible with the previous release.

Includes changes from intermediate releases:
- v1.15.2: Fixes CVE-2025-5283 (bug webm:413411335).
- v1.15.1: SO major version bump and changelog corrections.
- v1.15.0: New codec control for key frame filtering and RTC improvements.

Changelog: https://github.com/webmproject/libvpx/blob/v1.16.0/CHANGELOG
Signed-off-by: Luiz Angelo Daros de Luca <redacted>