Improve workspace-unsafe form validation.

Closes #3471675

core/modules/workspaces/src/Hook/EntityOperations.php

@@ -297,7 +297,7 @@ public function entityQueryTagLatestTranslatedAffectedRevisionAlter(QueryInterfa
    *
    * Alters entity forms to disallow concurrent editing in multiple workspaces.
    */
-  #[Hook('form_alter')]
+  #[Hook('form_alter', order: Order::First)]
   public function entityFormAlter(array &$form, FormStateInterface $form_state, string $form_id): void {
     if (!$form_state->getFormObject() instanceof EntityFormInterface) {
       return;