Fixes #1135 and #1136

[LaurentLesle]

Overview/Summary

Replace this with a brief description of what this Pull Request fixes, changes, etc.

This PR fixes/adds/changes/removes

1. Fixes Race condition results in InternalServerError when deploying in vhub a firewall, an express route gateway, vhub peering and routing intent #1135 - Race condition results in InternalServerError when deploying in vhub a firewall, an express route gateway, vhub peering and routing intent
2. Fixes Updating existing vnet dns_server with Azure firewall leads to azurerm_virtual_network error. #1136 - Updating existing vnet dns_server with Azure firewall leads to azurerm_virtual_network error.
3. Replace me

Breaking Changes

none

Testing Evidence

module.alz_connectivity.azurerm_virtual_hub_routing_intent.virtual_wan["/subscriptions/000000/resourceGroups/rg-prod-network-vwan/providers/Microsoft.Network/virtualHubs/lz-cl-hub-southeastasia/lz-cl-routingintent-southeastasia"]: Still creating... [6m40s elapsed]
module.alz_connectivity.azurerm_virtual_hub_routing_intent.virtual_wan["/subscriptions/000000/resourceGroups/rg-prod-network-vwan/providers/Microsoft.Network/virtualHubs/lz-cl-hub-southeastasia/lz-cl-routingintent-southeastasia"]: Creation complete after 6m41s [id=/subscriptions/000000/resourceGroups/rg-prod-network-vwan/providers/Microsoft.Network/virtualHubs/lz-cl-hub-southeastasia/routingIntent/lz-cl-routingintent-southeastasia]

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• Checked for duplicate Pull Requests
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