Import: Fix case where path to load is empty and root path is not

gadget/gadget_landing_cribjs.js

@@ -37,7 +37,8 @@
       if (path_to_load && !relativePath.startsWith("/") &&
           !path_to_load.endsWith("/")) {
         end_url = path_to_load + "/" + relativePath;
-      } else if (relativePath.startsWith("/") && path_to_load.endsWith("/")) {
+      } else if (relativePath.startsWith("/") &&
+                 (!path_to_load || path_to_load.endsWith("/"))) {
         end_url = path_to_load + relativePath.substring(1);
       } else {
         end_url = path_to_load + relativePath;