LibWeb: Port Worker to new String

Author: https://github.com/kennethmyhra
Commit: e905f25911
Pull-request: https://github.com/SerenityOS/serenity/pull/17577
Reviewed-by: https://github.com/AtkinsSJ

Userland/Libraries/LibWeb/HTML/Worker.idl

@@ -1,7 +1,7 @@
 #import <DOM/EventTarget.idl>
 #import <DOM/EventHandler.idl>
 
-[Exposed=(Window)]
+[Exposed=(Window), UseNewAKString]
 interface Worker : EventTarget {
     constructor(DOMString scriptURL, optional WorkerOptions options = {});