fix: ajustar expectativa de undefined/null en prueba AdminService

Co-authored-by: aider (openrouter/openai/gpt-5) <aider@aider.chat>

tests/unit/services/admin.test.ts

@@ -111,7 +111,7 @@ describe('AdminService - comandos básicos', () => {
     expect(Number(tcount.c)).toBe(0);
 
     const g = memdb.query(`SELECT 1 FROM groups WHERE id='g2@g.us'`).get() as any;
-    expect(g).toBeUndefined();
+    expect(g == null).toBe(true);
 
     const ag = memdb.query(`SELECT 1 FROM allowed_groups WHERE group_id='g2@g.us'`).get() as any;
     expect(ag).toBeUndefined();