LibWeb: Make factory method of DOM::HTMLCollection fallible

Author: https://github.com/kennethmyhra
Commit: ff875d353b
Pull-request: https://github.com/SerenityOS/serenity/pull/17491
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/HTML/HTMLFormElement.cpp

@@ -236,7 +236,7 @@ JS::NonnullGCPtr<DOM::HTMLCollection> HTMLFormElement::elements() const
     if (!m_elements) {
         m_elements = DOM::HTMLCollection::create(const_cast<HTMLFormElement&>(*this), [](Element const& element) {
             return is_form_control(element);
-        });
+        }).release_value_but_fixme_should_propagate_errors();
     }
     return *m_elements;
 }