The APV demuxer is new in ffmpeg 8.0, so ubuntu-24.04 runners failed instead of skipping. testkit gains ffmpeg_with_format_or_skip: when ffmpeg -formats does not list apv it SKIPs naming the detected version, failing only under FILMCRAFT_REQUIRE_ORACLES=1. The apv oracle uses it; docs/testing.md notes ffmpeg >= 8.0.
Fixes#1249.