remove wrong file and update default cluster role rule

Author: mainred

src/aks-agent/azext_aks_agent/agent/k8s/aks_agent_manager.py

@@ -785,11 +785,6 @@ def get_default_cluster_role(self) -> V1ClusterRole:
                 "resources": ["*"],
                 "verbs": ["get", "list", "watch"]
             },
-            {
-                "api_groups": [""],
-                "resources": ["pods/portforward"],
-                "verbs": ["create"]
-            }
         ]
         cluster_role = V1ClusterRole(
             metadata=client.V1ObjectMeta(