LibWeb: Explicitly ignore PageClient::m_console_clients

This map is managed entirely by manual insertion/removal when a document
is created/destroyed, so we should just ignore it in visit_edges().

Userland/Services/WebContent/PageClient.cpp

@@ -125,6 +125,7 @@ void PageClient::visit_edges(JS::Cell::Visitor& visitor)
 {
     Base::visit_edges(visitor);
     visitor.visit(m_page);
+    visitor.ignore(m_console_clients);
 }
 
 ConnectionFromClient& PageClient::client() const