remove check for jspsych object in example

examples/jspsych-extension-mouse-tracking.html

@@ -83,12 +83,7 @@
     }
   };
   
-  if (typeof jsPsych !== "undefined") {
-    jsPsych.run([trial_loop]);
-  } else {
-    document.body.innerHTML = '<div style="text-align:center; margin-top:50%; transform:translate(0,-50%);">You must be online to view the plugin demo.</div>';
-  }
-
+  jsPsych.run([trial_loop]);
 </script>
 
 </html>