Expose NT entry change time in PhotonLib (#562)

Adds target change timestamp to PhotonPipelineResult

Co-authored-by: Matt <matthew.morley.ca@gmail.com>

photon-lib/src/main/native/cpp/photonlib/PhotonCamera.cpp

@@ -72,6 +72,10 @@ PhotonPipelineResult PhotonCamera::GetLatestResult() {
   photonlib::Packet packet{bytes};
 
   packet >> result;
+
+  result.SetTimestamp(units::microsecond_t(rawBytesEntry.GetLastChange()) -
+                      result.GetLatency());
+
   return result;
 }