chore: Add tcl download file for qtox. #643

Job	Run time
buildfarm (server)	19s
build (alpine-s390x)	18s
buildfarm (worker)	14s
build (bazel)	3m 49s
build (compcert)	19s
build (doxygen)	26s
qtox-host-qt (6.2.4)	26s
build (flutter-web)	18s
qtox-host-qt (6.8.1)	25s
build (frama-c)	18s
build (freebsd)	17s
build (haskell)	16s
update-nightly-tag	3s
build (pkgsrc)	16s
qt-static-macos (arm64, 10.15)	32s
qt-static-macos (arm64, 12.0)	31s
qt-static-macos (x86_64, 10.15)	42s
qt-static-macos (x86_64, 12.0)	50s
qtox-android (armeabi-v7a, debug, 6.2.4)	19s
qtox (alpine)	18s
qtox (alpine-appimage)	31s
qtox-android (armeabi-v7a, debug, 6.8.1)	18s
qtox (alpine-static)	17s
qtox-android (armeabi-v7a, release, 6.2.4)	17s
qtox-android (armeabi-v7a, release, 6.8.1)	27s
qtox (debian)	21s
qtox-android (arm64-v8a, debug, 6.2.4)	32s
qtox (fedora)	17s
qtox-android (arm64-v8a, debug, 6.8.1)	27s
qtox (flatpak-builder)	16s
qtox-android (arm64-v8a, release, 6.2.4)	27s
qtox (ubuntu-lts)	17s
qtox-android (arm64-v8a, release, 6.8.1)	20s
qtox (wasm-builder)	29s
qtox (windows-builder.i686)	19s
qtox (windows-builder.x86_64)	23s
qtox-wasm-buildhome	2m 29s
	19m 23s

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