fix: Export JSInterface to window object to fix ReferenceError (#5674)

The constraints.js file expects JSInterface to be available as a global
variable, but interface.js was only exporting it for CommonJS (module.exports)
and not attaching it to the window object.

This commit adds the window export following the same pattern used in
export.js for Mouse and MusicBlocks classes.

Fixes: Uncaught ReferenceError: JSInterface is not defined at constraints.js:23:1

Author: vanshika2720

js/js-export/interface.js

@@ -1810,3 +1810,7 @@ class JSInterface {
 if (typeof module !== "undefined" && module.exports) {
     module.exports = JSInterface;
 }
+
+if (typeof window !== "undefined") {
+    window.JSInterface = JSInterface;
+}