LibURL+LibWeb: Make URL serialization return a String

This can only ever fail from OOM, and will never by string containing
random byte sequences.

Libraries/LibWeb/HTML/HTMLHyperlinkElementUtils.cpp

@@ -52,7 +52,7 @@ String HTMLHyperlinkElementUtils::origin() const
         return String {};
 
     // 3. Return the serialization of this element's url's origin.
-    return MUST(String::from_byte_string(m_url->origin().serialize()));
+    return m_url->origin().serialize();
 }
 
 // https://html.spec.whatwg.org/multipage/links.html#dom-hyperlink-protocol