LibWeb: Convert ShadowRoot to use TRY for error propagation

Userland/Libraries/LibWeb/DOM/ShadowRoot.cpp

@@ -39,9 +39,7 @@ String ShadowRoot::inner_html() const
 // https://w3c.github.io/DOM-Parsing/#dom-innerhtml-innerhtml
 ExceptionOr<void> ShadowRoot::set_inner_html(String const& markup)
 {
-    auto result = DOMParsing::inner_html_setter(*this, markup);
-    if (result.is_exception())
-        return result.exception();
+    TRY(DOMParsing::inner_html_setter(*this, markup));
 
     set_needs_style_update(true);
     return {};