Add Route Table Association Dependency to AKS Firewall

[athiththan11]

Purpose

Add the AKS Subnet Route Table association as a dependency to the creation of AKS Cluster in the AKS-Firewall module. This helps preventing the following error behaviour when spinning a new environment.

Error: creating Managed Cluster (Subscription: "xxxx"
Resource Group Name: "rg-xxxxx"
Managed Cluster Name: "aks-xxxx"): managedclusters.ManagedClustersClient#CreateOrUpdate: Failure sending request: StatusCode=0 -- Original Error: Code="ExistingRouteTableNotAssociatedWithSubnet" Message="An existing route table has not been associated with subnet /subscriptions/xxxx/resourceGroups/rg-xxx/providers/Microsoft.Network/virtualNetworks/vnet-xxxx/subnets/snet-xxxx. Please update the route table association"