LibWeb: Amend Element interface to make it compatible with TrustedTypes

Author: https://github.com/tete17
Commit: db41ea8117
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/6057
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/Lubrsi ✅

Libraries/LibWeb/HTML/HTMLSelectElement.cpp

@@ -612,7 +612,7 @@ void HTMLSelectElement::create_shadow_tree_if_needed()
         height: 16px;
         margin-left: 4px;
     )~~~"_string));
-    MUST(m_chevron_icon_element->set_inner_html(chevron_svg));
+    MUST(m_chevron_icon_element->set_inner_html(Utf16String::from_utf8(chevron_svg)));
     MUST(border->append_child(*m_chevron_icon_element));
 
     update_inner_text_element();