LibJS+LibWeb: Convert empty PrimitiveString instances to String

Author: https://github.com/trflynn89
Commit: 49e8dcf0b2
Pull-request: https://github.com/SerenityOS/serenity/pull/17388
Reviewed-by: https://github.com/linusg

Userland/Libraries/LibWeb/XHR/XMLHttpRequest.cpp

@@ -129,7 +129,7 @@ WebIDL::ExceptionOr<JS::Value> XMLHttpRequest::response()
     if (m_response_type == Bindings::XMLHttpRequestResponseType::Empty || m_response_type == Bindings::XMLHttpRequestResponseType::Text) {
         // 1. If this’s state is not loading or done, then return the empty string.
         if (m_state != State::Loading && m_state != State::Done)
-            return JS::PrimitiveString::create(vm, "");
+            return JS::PrimitiveString::create(vm, String {});
 
         // 2. Return the result of getting a text response for this.
         return JS::PrimitiveString::create(vm, get_text_response());