fix(react): guard against undefined 48357typeof in check()

The check() function assumes Component['48357typeof'] is always defined
when typeof Component === 'object', but non-React component objects
(e.g. Svelte components imported via barrel) may not have 48357typeof.
Calling .toString() on undefined throws TypeError.

Add a null guard so the check returns false for non-React components
instead of crashing.

Author: Clickin

packages/integrations/react/src/server.ts

@@ -23,7 +23,8 @@ async function check(
 	// Note: there are packages that do some unholy things to create "components".
 	// Checking the $$typeof property catches most of these patterns.
 	if (typeof Component === 'object') {
-		return Component['$$typeof'].toString().slice('Symbol('.length).startsWith('react');
+		const $$typeof = Component['$$typeof'];
+		return $$typeof != null && $$typeof.toString().slice('Symbol('.length).startsWith('react');
 	}
 	if (typeof Component !== 'function') return false;
 	if (Component.name === 'QwikComponent') return false;