MHSM Enable Purge Protection broken

### **This is autogenerated. Please review and update as needed.**

## Describe the bug

**Command Name**
`az keyvault update-hsm`

**Errors:**
```
(400) ByPass property is invalid. Supported values are : None, AzureServices

```

## To Reproduce:
Steps to reproduce the behavior. Note that argument values have been redacted, as they may contain sensitive information.

- _Put any pre-requisite steps here..._
- I was attempting to enabled purge protection, however, it seems `update-hsm` is hard-coded to only allow updates on firewall properties?
- `az keyvault update-hsm --hsm-name {} --enable-purge-protection`
- also tried below, which is documented here: https://docs.microsoft.com/en-us/azure/key-vault/managed-hsm/recovery?tabs=azure-cli#managed-hsm-cli
- `az keyvault update-hsm --subscription {} -g {} --hsm-name {} --enable-purge-protection true`

## Expected Behavior
Enable purge protection on MHSM.

## Environment Summary
```
Linux-4.15.0-142-generic-x86_64-with-debian-buster-sid
Python 3.6.10
Installer: DEB

azure-cli 2.26.0

Extensions:
azure-devops 0.18.0

```
## Additional Context