WebContent: Remove unnecessary [[maybe_unused]] attributes

Noticed while copy-pasting this method to a did-click-link method.

Userland/Services/WebContent/PageClient.cpp

@@ -324,7 +324,7 @@ void PageClient::page_did_unhover_link()
     client().async_did_unhover_link(m_id);
 }
 
-void PageClient::page_did_middle_click_link(URL::URL const& url, [[maybe_unused]] ByteString const& target, [[maybe_unused]] unsigned modifiers)
+void PageClient::page_did_middle_click_link(URL::URL const& url, ByteString const& target, unsigned modifiers)
 {
     client().async_did_middle_click_link(m_id, url, target, modifiers);
 }