feat: add agent_card to agent engine spec

PiperOrigin-RevId: 821726573

Author: vertex-sdk-bot

vertexai/_genai/agent_engines.py

@@ -1076,6 +1076,11 @@ def _create_config(
                 _agent_engines_utils._get_agent_framework(agent=agent)
             )
             update_masks.append("spec.agent_framework")
+
+            agent_engine_spec["agent_card"] = getattr(
+                getattr(agent, "agent_card", None), "model_dump_json", lambda: None
+            )()
+
             config["spec"] = agent_engine_spec
         if update_masks and mode == "update":
             config["update_mask"] = ",".join(update_masks)