Assert that version checking won't throw on startup (#1512)

# Overview

Previously if the coproc came up later, getProperty would return the
string literal "null", which made us print the BFW. Add tests to make
sure that we don't do that anymore by rebooting a sim coproc +
robot in a combination of different orders.

photon-lib/src/main/java/org/photonvision/simulation/PhotonCameraSim.java

@@ -68,7 +68,7 @@ import org.photonvision.targeting.PnpResult;
 public class PhotonCameraSim implements AutoCloseable {
     private final PhotonCamera cam;
 
-    NTTopicSet ts = new NTTopicSet();
+    protected NTTopicSet ts = new NTTopicSet();
     private long heartbeatCounter = 1;
 
     /** This simulated camera's {@link SimCameraProperties} */