Refine "Networking" tab's wording when Azure Application Gateway is enabled

[zhengchang907]

When Azure Application Gateway is enabled, the current wording "When creating a new virtual network, the subnet's address prefix is calculated automatically based on the virtual network's address prefix. When using an existing virtual network, a minimum virtual network size of /28 and a minimum subnet size of /29 are required. Additionally, the subnet must have adequate available addresses for the server setup." is not suitable.

Make this infobox only visible when Azure Application Gateway is disabled, add another infobox with wording "When creating a new virtual network, the subnet's address prefix is calculated automatically based on the virtual network's address prefix. When using an existing virtual network, a minimum virtual network size of /23 is required. For the Azure Application Gateway, a minimum subnet size of /24 is required and for JBoss cluster, a minimum subnet size of /29 is required. Additionally, the subnet must have adequate available addresses for the server setup."

This change needs to be applied to all multivm and VMSS offers.