Fix command line in simulator

In the original movement, the 'usb enabled' check was overridden
to true for the simulator such that shell_task() would always
be executed. In the new 'dummy' device in gossamer used by the
simulator, this usb check returns false.

Seemed like a slightly cleaner thing to do was to call
shell_task() regardless rather than to incorrectly
pretend that USB was connected.

movement.c

@@ -945,10 +945,14 @@ bool app_loop(void) {
         }
     }
 
+#if __EMSCRIPTEN__
+    shell_task();
+#else
     // if we are plugged into USB, handle the serial shell
     if (usb_is_enabled()) {
         shell_task();
     }
+#endif
 
     event.subsecond = 0;