Added Azure PowerShell command to deploy second ExpressRoute Gateway with admin state set to disabled

I have added Azure PowerShell command to deploy second ExpressRoute Gateway with admin state set to disabled as the corresponding option is not available through Azure Portal and CLI.

Author: hisriram1996

articles/expressroute/expressroute-howto-gateway-migration-portal.md

@@ -21,7 +21,7 @@ When creating an ExpressRoute virtual network gateway, you must select a [gatewa
 - Ensure you have an existing [ExpressRoute virtual network gateway](expressroute-howto-add-gateway-portal-resource-manager.md) in your Azure subscription.
 
 > [!TIP]
-> You can now deploy two ExpressRoute gateways within the same virtual network. To do this, create a second ExpressRoute gateway with its admin state set to **disabled**. Once the second gateway is deployed, initiate the *Prepare* step in the migration tool. This step establishes the connection without redeploying the gateway, as it's already in place. Finally, run the *Migrate* step, which will change the new gateway's admin state to **_enabled_**, completing the migration process. This method minimizes the migration or maintenance window, significantly reducing downtime when transitioning from a non-zonal to a zone-redundant gateway.
+> You can now deploy two ExpressRoute gateways within the same virtual network. To do this, create a second ExpressRoute gateway with its admin state set to **disabled**. Once the second gateway is deployed, initiate the *Prepare* step in the migration tool. This step establishes the connection without redeploying the gateway, as it's already in place. Finally, run the *Migrate* step, which will change the new gateway's admin state to **_enabled_**, completing the migration process. The second ExpressRoute Gateway can be deployed admin state set to **disabled** using Azure PowerShell command [**New-AzVirtualNetworkGateway**](https://learn.microsoft.com/en-in/powershell/module/az.network/new-azvirtualnetworkgateway) with the flag **-AdminState "Disabled"**. This method minimizes the migration or maintenance window, significantly reducing downtime when transitioning from a non-zonal to a zone-redundant gateway.
 
 ## Steps to migrate to a new gateway in Azure portal
 
@@ -66,4 +66,4 @@ Follow these steps to migrate to a new gateway using the Azure portal:
 ## Next steps
 
 * Learn more about [designing for high availability](designing-for-high-availability-with-expressroute.md).
-* Plan for [disaster recovery](designing-for-disaster-recovery-with-expressroute-privatepeering.md) and [using VPN as a backup](use-s2s-vpn-as-backup-for-expressroute-privatepeering.md).
+* Plan for [disaster recovery](designing-for-disaster-recovery-with-expressroute-privatepeering.md) and [using VPN as a backup](use-s2s-vpn-as-backup-for-expressroute-privatepeering.md).