fix(Browser history): fixed NPE when navigating a study via browser history and history navigation is now available via the navigateHistory command (#3337)

* fix(Browser history):
- fixed an NPE when navigating to a different study via the URL
- exposed browser history navigation via a command

* Added documentation for the navigateHistory command.
Moved the history object from UI to viewer.

extensions/measurement-tracking/src/contexts/TrackedMeasurementsContext/TrackedMeasurementsContext.tsx

@@ -149,6 +149,10 @@ function TrackedMeasurementsContextProvider(
         activeViewport.displaySetInstanceUIDs[0]
       );
 
+      if (!displaySet) {
+        return;
+      }
+
       // If this is an SR produced by our SR SOPClassHandler,
       // and it hasn't been loaded yet, do that now so we
       // can check if it can be rehydrated or not.