Flag --max-surge in az aks nodepool upgrade has no effect

> ### `az feedback` auto-generates most of the information requested below, as of CLI version 2.0.62

**Describe the bug**

Flag `--max-surge` in `az aks nodepool upgrade` has no effect.
You need to issue a `az aks nodepool update --max-surge=N` before running the upgrade to actually be able to use the surge.

**To Reproduce**

Run this on an AKS nodepool and observe a single extra node gets created instead of 5:
`az aks nodepool upgrade --max-surge 5`

**Expected behavior**

The flag should perform the upgrade with the provided number of surge nodes.
At the very least, the flag should not be available if the only way (API-wise) is to run the update command first.

**Environment summary**

```
# az version
{
"azure-cli": "2.28.0",
"azure-cli-core": "2.28.0",
"azure-cli-telemetry": "1.0.6",
"extensions": {
"aks-preview": "0.5.34",
"subscription": "0.1.4"
}
}
```
AKS v1.20.9

**Additional context**