testffmpeg: avutil queue family version check

[ColinKinloch]

The AVVulkanDeviceQueueFamily struct was introduced by libavutil 59.34.100: FFmpeg/FFmpeg@13489c8 .

This test would fail to build with FFmpeg 7.0.3 "Dijkstra", for example flatpak org.freedesktop.Platform//24.08.

You can test this with:

flatpak install org.freedesktop.Sdk//24.08
flatpak run --filesystem="$(pwd)" org.freedesktop.Sdk//24.08 -c 'cmake -B _build_fp -G Ninja -DSDL_TESTS=ON -DCMAKE_EXPORT_COMPILE_COMMANDS=ON'
flatpak run --filesystem="$(pwd)" org.freedesktop.Sdk//24.08 -c 'cmake --build _build_fp'
SDL_LOGGING=system=debug flatpak run --devel --filesystem="$(pwd)" --device=dri --socket=wayland org.freedesktop.Sdk//24.08 -c './_build_fp/test/testffmpeg'