Circular reference when trying to create application gateway without a public ip address

### Describe the bug

It seems that it is not possible to create an application gateway without a public ip address but when you try, the messaging refers you to one of the other skus. Standar or WAF are deprecated and refer you to use Standard_v2 or WAF_v2, when you try those, they say that you can't create those without public ip addresses and refer you back to Standard and WAF sku's.

The problem is the messaging in the azure cli for creation.

If you pick Standard_v2 or WAF_v2 as the sku, it tells you that "does not support Application Gateway without Public IP for the selected SKU tier Standard_v2. Supported SKU tiers are Standard,WAF."

However those 2 skus (Standard, WAF) have been deprecated and it won't let you create resources with those sku's
"Application Gateway SKU tier Standard has been deprecated. Supported SKU tiers are Standard_v2,WAF_v2"

### Related command

az network application-gateway create --name $gatewayname `
--min-capacity 0 `
--max-capacity 2 `
--resource-group $TargetResourceGroup `
--location uksouth `
--sku Standard_v2 `
--subnet $subnet.id `
--http2 Enabled `
--priority 5000 `
--http-settings-port 80 `
--http-settings-protocol Http `
--frontend-port 80 `
--public-ip-address "''" `
--private-ip-address $privateip `

az network application-gateway create --name $gatewayname `
--capacity 2 `
--resource-group $TargetResourceGroup `
--location uksouth `
--sku Standard_small `
--subnet $subnet.id `
--http2 Enabled `
--priority 5000 `
--http-settings-port 80 `
--http-settings-protocol Http `
--frontend-port 80 `
--public-ip-address "''" `
--private-ip-address $privateip

### Errors

[ApplicationGatewayId] does not support Application Gateway without Public IP for the selected SKU tier Standard_v2. Supported SKU tiers are Standard,WAF.

Application Gateway SKU tier Standard has been deprecated. Supported SKU tiers are Standard_v2,WAF_v2

### Issue script & Debug output

n/a the problem isn't with the command itself but with the messaging

### Expected behavior

Error messages should be correct to avoid waisting time trying different combinations that don't work; in this case the user shoudl just be told that Application gateways cannot be created withou public ip addresses.

### Environment Summary

{
"azure-cli": "2.50.0",
"azure-cli-core": "2.50.0",
"azure-cli-telemetry": "1.0.8",
"extensions": {
"storage-preview": "0.9.0"
}
}

### Additional context

_No response_