`New-AzApplicationGateway` parameter sets don't allow using `UserAssignedIdentityId` and `FirewallPolicyId` together

### Description

See title

### Issue script & Debug output

```PowerShell
Parameter set cannot be resolved using the specified named parameters. One or more parameters issued cannot be used together or an insufficient number of parameters were provided.
```

### Environment data

```PowerShell
Name Value
---- -----
PSVersion 7.4.1
PSEdition Core
GitCommitId 7.4.1
OS Microsoft Windows 10.0.22631
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0
```

### Module versions

```PowerShell
ModuleType Version PreRelease Name
---------- ------- ---------- ----
Script 2.15.1 Az.Accounts
Script 5.0.1 Az.Monitor
Script 7.4.0 Az.Network
```

### Error output

_No response_