ffmpeg4: Update to ffmpeg-4.4.6 #786

Job	Run time
commit-message	5s
what-changed	26s
show-vars	2s
pkglint	48s
build-qemu (openbsd-7.6-x86_64, openbsd, x86-64, 7.6)	6m 30s
build-qemu (freebsd-14.2-x86_64, freebsd, x86-64, 14.2)	9m 4s
build-native (cygwin-2022-x86_64, windows-2022)	1h 31m 20s
build-native (macos-13-x86_64, macos-13)	1s
build-native (ubuntu-24.04-x86_64, ubuntu-24.04)	6m 45s
jenkins / trigger	32m 39s
build-native (macos-15-arm64, macos-15)	6m 56s
jenkins / build (netbsd-10-x86_64, https://ci.dreckly.dev/job/check-commit/check-commit=netbsd-10-x86_64/10...	2m 17s
jenkins / build (centos-7-x86_64, https://ci.dreckly.dev/job/check-commit/check-commit=centos-7-x86_64/1065/)	2m 18s
jenkins / build (smartos-24-x86_64, https://ci.dreckly.dev/job/check-commit/check-commit=smartos-24-x86_64/...	4m 37s
	2h 43m 48s

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