chore: ensure we null effect fields (#13529)

Author: trueadm

packages/svelte/src/internal/client/reactivity/effects.js

@@ -407,6 +407,10 @@ export function destroy_effect(effect, remove_dom = true) {
 		unlink_effect(effect);
 	}
 
+	if (DEV) {
+		effect.component_function = null;
+	}
+
 	// `first` and `child` are nulled out in destroy_effect_children
 	effect.next =
 		effect.prev =