Update tests/server/routes/test_agent_card_route.py

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: guglielmo-san

tests/server/routes/test_agent_card_route.py

@@ -47,7 +47,7 @@ async def modifier(card):
 
     card_route = AgentCardRoutes(mock_agent_card, card_modifier=modifier)
     app = Starlette()
-    app.routes.append(card_route.route)
+    app.routes.append(card_route.routes[0])
     client = TestClient(app)
 
     response = client.get('/')