Allow aprilrobotics to start without camera extrinsics

This makes it so that it doesn't crash-loop prior to having extrinsics.

Change-Id: Ib7f494d5b2ab1504a6bffa0ed7606097707dc47c
Signed-off-by: James Kuszmaul <jabukuszmaul@gmail.com>
diff --git a/y2023/vision/vision_util.h b/y2023/vision/vision_util.h
index ce1a69d..79f5c92 100644
--- a/y2023/vision/vision_util.h
+++ b/y2023/vision/vision_util.h
@@ -10,7 +10,7 @@
 const frc971::vision::calibration::CameraCalibration *FindCameraCalibration(
     const y2023::Constants &calibration_data, std::string_view node_name);
 
-cv::Mat CameraExtrinsics(
+std::optional<cv::Mat> CameraExtrinsics(
     const frc971::vision::calibration::CameraCalibration *camera_calibration);
 
 cv::Mat CameraIntrinsics(