overlay_cuda cannot be control by ZMQ but overlay can

[Théo]

Summary of the bug:
How to reproduce:

ffmpeg -re -loglevel verbose -report -i bbb_sunflower_1080p_30fps_normal.mp4 -i  bbb_sunflower_1080p_30fps_normal.mp4 -filter_complex "[0:v]hwupload_cuda,format=pix_fmts=cuda[v0];[1:v]hwupload_cuda,format=pix_fmts=cuda[v1];[v0][v1]overlay_cuda=x=0:y=0,zmq[vv]" -map "[vv]" -an -c:v h264_nvenc  -f null /dev/null

ffmpeg version n5.1.2-1-g8cf653b7e1 Copyright (c) 2000-2022 the FFmpeg developers
  built with gcc 10 (Debian 10.2.1-6)
  configuration: --enable-libzmq --enable-libndi_newtek --enable-gpl --enable-cuda-nvcc --enable-libnpp --enable-cuda --enable-cuvid --enable-nvenc --extra-cflags='-I/root/decklink/include -I/usr/local/cuda/include' --extra-ldflags='-L/root/decklink/include -L/usr/local/cuda/lib64' --enable-nonfree --enable-libmp3lame --disable-ffplay --enable-opencl

When sending 'Parsed_overlay_cuda_4' with ZMQ it return b'38 Function not implemented' while the same command with a CPU overlay works flawlessly.

[Théo]

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