avif: always indicate endless loop
avif does not support loops but endless loop was the behavior before 460085 was fixed, so a workaround is added.
See also: https://github.com/AOMediaCodec/libavif/issues/347
avif does not support loops but endless loop was the behavior before 460085 was fixed, so a workaround is added.
See also: https://github.com/AOMediaCodec/libavif/issues/347