Enable orch_northbond_route_zmq_enabled feature in sonic-mgmt test. (#20441)

Enable orch_northbond_route_zmq_enabled feature in sonic-mgmt test.

Why I did it
Test orch_northbond_route_zmq_enabled in PR validation and nightly test.

These change added in #19446, but been reverted by: #20261
Add change back and set buffer_model to traditional to prevent regression.

Work item tracking
Microsoft ADO (number only): 32582830

How I did it
Enable orch_northbond_route_zmq_enabled in golden config.
Set buffer_model to traditional to prevent regression.

How to verify it
Pass all test case.

Author: liuh-80

ansible/library/generate_golden_config_db.py

@@ -533,6 +533,38 @@ def update_dns_config(self, config):
         else:
             return config
 
+    def generate_default_init_config_db(self):
+        rc, out, err = self.module.run_command("sonic-cfggen -H -m -j /etc/sonic/init_cfg.json --print-data")
+        if rc != 0:
+            self.module.fail_json(msg="Failed to get config from minigraph: {}".format(err))
+
+        # Generate config table from init_cfg.ini
+        ori_config_db = json.loads(out)
+
+        golden_config_db = {}
+        if "DEVICE_METADATA" in ori_config_db:
+            golden_config_db["DEVICE_METADATA"] = ori_config_db["DEVICE_METADATA"]
+
+        # Set buffer_model to traditional to prevent regression, as it is currently hardcoded here:
+        #     https://github.com/sonic-net/sonic-utilities/blob/19594b99129f3c881d500ff65d4955d077accb25/config/main.py#L2216
+        golden_config_db["DEVICE_METADATA"]["localhost"]["buffer_model"] = "traditional"
+
+        return json.dumps(golden_config_db, indent=4)
+
+    def update_zmq_config(self, config):
+        ori_config_db = json.loads(config)
+        if "DEVICE_METADATA" not in ori_config_db:
+            ori_config_db["DEVICE_METADATA"] = {}
+        if "localhost" not in ori_config_db["DEVICE_METADATA"]:
+            ori_config_db["DEVICE_METADATA"]["localhost"] = {}
+
+        # Older version image may not support ZMQ feature flag
+        rc, out, err = self.module.run_command("sudo cat /usr/local/yang-models/sonic-device_metadata.yang")
+        if "orch_northbond_route_zmq_enabled" in out:
+            ori_config_db["DEVICE_METADATA"]["localhost"]["orch_northbond_route_zmq_enabled"] = "true"
+
+        return json.dumps(ori_config_db, indent=4)
+
     def generate_lt2_ft2_golden_config_db(self):
         """
         Generate golden_config for FT2 to enable FEC.
@@ -575,7 +607,10 @@ def generate(self):
         elif self.topo_name in ["t1-filterleaf-lag"]:
             config = self.generate_filterleaf_golden_config_db()
         else:
-            config = "{}"
+            config = self.generate_default_init_config_db()
+
+        # update ZMQ config
+        config = self.update_zmq_config(config)
 
         # update dns config
         config = self.update_dns_config(config)