jellyfin-ffmpeg: add to release-cuda (#423220)

pkgs/top-level/release-cuda.nix

···
       gimp3 = linux;
       gpu-screen-recorder = linux;
       gst_all_1.gst-plugins-bad = linux;
+      jellyfin-ffmpeg = linux;
       kdePackages.kdenlive = linux;
       lightgbm = linux;
       llama-cpp = linux;