CEC-2211 Add CAN signals component to map (#182)

Fix timer memory leak

src/components/DigitalTwin/index.js

@@ -18,6 +18,9 @@ const DigitalTwin = (props) => {
 
   return (
     <div>
+      {!battery && !doors && !location && !windows && (
+        <p>No vehicle data to display.</p>
+      )}
       {battery != null && keyValueTemplate("Battery", `${battery.percent}%`)}
       {doors != null && (
         <div className={classes.popupSection}>