[Feature]: Add warning for users of eventual change of default for "az network lb create" and "az network lb frontend-ip create"

[brianlehr]

In the latest profile and the profiles that use the same api-version as latest profile, the default public IP used for creation for an LB frontend with "az network lb create" and/or "az network lb frontend-ip create" will be changed from Basic to Standard. In advance of eventual breaking change, would like to add warning for users.

Similar change done for "az vm create" - #18662

[yonzhan]

network

[brianlehr]

@necusjz @YuanyuanNi I am not seeing this as completed when I test with latest cloud shell. Please show me if this is wrong. otherwise we need to re-open this issue.

brian@Azure:~$ az network lb create --name testinglbbasic --resource-group upgradetest --location westus
{
"loadBalancer": {
"backendAddressPools": [
{
"etag": "W/"76bf8845-6c44-4d33-bfd0-fcb4a317b462"",
"id": "/subscriptions/6bb4a28a-db84-4e8a-b1dc-fabf7bd9f0b2/resourceGroups/upgradetest/providers/Microsoft.Network/loadBalancers/testinglbbasic/backendAddressPools/testinglbbasicbepool",
"name": "testinglbbasicbepool",
"properties": {
"provisioningState": "Succeeded"
},
"resourceGroup": "upgradetest",
"type": "Microsoft.Network/loadBalancers/backendAddressPools"
}
],
"frontendIPConfigurations": [
{
"etag": "W/"76bf8845-6c44-4d33-bfd0-fcb4a317b462"",
"id": "/subscriptions/6bb4a28a-db84-4e8a-b1dc-fabf7bd9f0b2/resourceGroups/upgradetest/providers/Microsoft.Network/loadBalancers/testinglbbasic/frontendIPConfigurations/LoadBalancerFrontEnd",
"name": "LoadBalancerFrontEnd",
"properties": {
"privateIPAllocationMethod": "Dynamic",
"provisioningState": "Succeeded",
"publicIPAddress": {
"id": "/subscriptions/6bb4a28a-db84-4e8a-b1dc-fabf7bd9f0b2/resourceGroups/upgradetest/providers/Microsoft.Network/publicIPAddresses/PublicIPtestinglbbasic",
"resourceGroup": "upgradetest"
}
},
"resourceGroup": "upgradetest",
"type": "Microsoft.Network/loadBalancers/frontendIPConfigurations"
}
],
"inboundNatPools": [],
"inboundNatRules": [],
"loadBalancingRules": [],
"probes": [],
"provisioningState": "Succeeded",
"resourceGuid": "3ca992e4-8bfe-48bd-96fb-c640eb93cb39"
}
}

[necusjz]

@brianlehr, sorry for the inconvenience, it will be fixed by #22339.

[brianlehr]

I see the warning now, thank you @necusjz