LibWeb: Do not allow focusing "Actually Disabled" elements

Author: https://github.com/Simek
Commit: 09420406b8
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/2128

Userland/Libraries/LibWeb/HTML/HTMLSelectElement.cpp

@@ -613,4 +613,10 @@ void HTMLSelectElement::update_selectedness(JS::GCPtr<HTML::HTMLOptionElement> l
     }
     update_inner_text_element();
 }
+
+bool HTMLSelectElement::is_focusable() const
+{
+    return enabled();
+}
+
 }