fix incomplete FfiRequest when converting video frames (#299)

Author: theomonnom

livekit-rtc/livekit/rtc/video_frame.py

@@ -116,6 +116,7 @@ def _proto_info(self) -> proto_video.VideoBufferInfo:
         info.height = self.height
         info.type = self.type
         info.data_ptr = addr
+        info.stride = 0
 
         if self.type in [
             proto_video.VideoBufferType.ARGB,