`Microsoft.ContainerService` - some `loadBalancerProfile` properties can be set when `outboundType` is set to `userAssignedNATGateway``

Service: `Container Service`
API Version: `2022-09-02-preview`

According to the [MSFT docs](https://learn.microsoft.com/en-us/azure/virtual-network/nat-gateway/nat-overview?WT.mc_id=AZ-MVP-5000119#outbound-connectivity) a NAT Gateway assigned to a subnet will take precedence over any load balancer rules assigned to the same subnet.

In AKS when `outboundType` is set to `userAssignedNATGateway` some `loadBalancerProfile` properties such as `outboundIPPrefixes` can be sent to the API and are accepted but do not actually seem to be set or returned by the API:

The PUT
```
...
"networkProfile": {
"dnsServiceIP": "10.0.0.10",
"dockerBridgeCidr": "172.17.0.1/16",
"loadBalancerProfile": {
"allocatedOutboundPorts": 0,
"idleTimeoutInMinutes": 4,
"outboundIPPrefixes": {
"publicIPPrefixes": [
{
"id": "/subscriptions/***/resourceGroups/***/providers/Microsoft.Network/publicIPPrefixes/acctestipprefix230206112441903773"
}
]
}
},
"loadBalancerSku": "standard",
"networkMode": "",
"networkPlugin": "azure",
"networkPolicy": "",
"outboundType": "userAssignedNATGateway",
"podCidrs": [],
"serviceCidr": "10.0.0.0/16",
"serviceCidrs": []
},
...
```

The GET
```
...
"networkProfile": {
"networkPlugin": "azure",
"loadBalancerSku": "Standard",
"loadBalancerProfile": {
"allocatedOutboundPorts": 0,
"idleTimeoutInMinutes": 4,
"backendPoolType": "nodeIPConfiguration"
},
"serviceCidr": "10.0.0.0/16",
"dnsServiceIP": "10.0.0.10",
"dockerBridgeCidr": "172.17.0.1/16",
"outboundType": "userAssignedNATGateway",
"serviceCidrs": [
"10.0.0.0/16"
],
"ipFamilies": [
"IPv4"
]
},
...
```

In addition some properties are accepted and appear to be set on the cluster e.g. `outboundIPs`

The PUT
```
...
"networkProfile": {
"dnsServiceIP": "10.0.0.10",
"dockerBridgeCidr": "172.17.0.1/16",
"loadBalancerProfile": {
"allocatedOutboundPorts": 0,
"idleTimeoutInMinutes": 4,
"outboundIPs": {
"publicIPs": [
{
"id": "/subscriptions/1a6092a6-137e-4025-9a7c-ef77f76f2c02/resourceGroups/acctestRG-aks-230206133925446833/providers/Microsoft.Network/publicIPAddresses/acctest-PIP-230206133925446833"
}
]
}
},
"loadBalancerSku": "standard",
"networkMode": "",
"networkPlugin": "azure",
"networkPolicy": "",
"outboundType": "userAssignedNATGateway",
"podCidrs": [],
"serviceCidr": "10.0.0.0/16",
"serviceCidrs": []
},
...
```

The GET
```
...
"networkProfile": {
"networkPlugin": "azure",
"loadBalancerSku": "Standard",
"loadBalancerProfile": {
"outboundIPs": {
"publicIPs": [
{
"id": "/subscriptions/1a6092a6-137e-4025-9a7c-ef77f76f2c02/resourceGroups/acctestRG-aks-230206133925446833/providers/Microsoft.Network/publicIPAddresses/acctest-PIP-230206133925446833"
}
]
},
"allocatedOutboundPorts": 0,
"idleTimeoutInMinutes": 4,
"backendPoolType": "nodeIPConfiguration"
},
"serviceCidr": "10.0.0.0/16",
"dnsServiceIP": "10.0.0.10",
"dockerBridgeCidr": "172.17.0.1/16",
"outboundType": "userAssignedNATGateway",
"serviceCidrs": [
"10.0.0.0/16"
],
"ipFamilies": [
"IPv4"
]
},
...
```

Given the docs mentioned above this configuration doesn't seem applicable or relevant. Could we get some clarification in the AKS docs regarding this and have the API return an error if the configuration isn't valid?

Start with the Microsoft.ContainerService API version 2022-09-02-preview schema and the AKS outbound connectivity documentation linked in the issue. Compare the PUT and GET networkProfile examples for outboundType userAssignedNATGateway, then clarify the applicable properties and validation expectations; done means the documentation and API behavior no longer accept or imply unsupported configuration.

Written by the indexing model from the issue text.