Disable debugger logic when not active

This fixes a bug where you could still drag an entity around with the
debugger inactive if you were holding the entity while disabling the
debugger with Y. Furthermore, you couldn't even drop the entity even if
you wanted to.

desktop_version/src/LevelDebugger.cpp

@@ -191,6 +191,11 @@ namespace level_debugger
 
     void logic(void)
     {
+        if (!active)
+        {
+            return;
+        }
+
         if (INBOUNDS_VEC(held_entity, obj.entities))
         {
             int new_xp = key.mousex - grabber_offset_x;