fix the cni to azure in agic addon

Author: akshaysngupta

src/aks-preview/azext_aks_preview/tests/latest/test_aks_commands.py

@@ -744,6 +744,7 @@ def test_aks_create_with_ingress_appgw_addon(
         create_cmd = (
             "aks create --resource-group={resource_group} --name={name} --enable-managed-identity "
             "-a ingress-appgw --appgw-subnet-cidr 10.232.0.0/16 "
+            "--network-plugin azure "
             "--ssh-key-value={ssh_key_value} -o json"
         )
         self.cmd(
@@ -782,6 +783,7 @@ def test_aks_byo_subnet_with_ingress_appgw_addon(
         # create virtual network
         create_vnet = (
             "network vnet create --resource-group={resource_group} --name={vnet_name} "
+            "--network-plugin azure "
             "--address-prefix 11.0.0.0/16 --subnet-name aks-subnet --subnet-prefix 11.0.0.0/24  -o json"
         )
         vnet = self.cmd(
@@ -857,6 +859,7 @@ def test_aks_byo_appgw_with_ingress_appgw_addon(
         # create virtual network
         create_vnet = (
             "network vnet create --resource-group={resource_group} --name={vnet_name} "
+            "--network-plugin azure "
             "--address-prefix 11.0.0.0/16 --subnet-name aks-subnet --subnet-prefix 11.0.0.0/24 -o json"
         )
         vnet = self.cmd(