'MultiplePersistent' value for LoadBalancerType parameter missing from Az.DesktopVirtualization

### Description

A [recently introduced public preview feature](https://techcommunity.microsoft.com/blog/azurevirtualdesktopblog/in-public-preview-multiple-personal-desktops-with-azure-virtual-desktop/4394696) has added a 'MultiplePersistent' value for the 'LoadBalancerType' parameter, but the Az.DesktopVirtualization module has not been updated to accommodate. This prevents the use of 'New-AzWvdRegistrationInfo' on host pools where this LoadBalancerType has been set, and possibly other commands.

### Issue script & Debug output

```PowerShell
PS C:\Windows\system32> New-AzWvdRegistrationInfo -ResourceGroupName $hostPool.ResourceGroupName -HostPoolName $hostPool.Name -ExpirationTime $((Get-Date).ToUniversalTime().AddDays($tokenTTL).ToString('yyyy-MM-ddTHH:mm:ss.fffffffZ'))
Az.DesktopVirtualization\New-AzWvdHostPool : ActivityId: 63624f0d-c24d-4433-8637-52f51a5e2783 Error: This endpoint is not available in api-version 2024-04-03
At C:\Program Files\WindowsPowerShell\Modules\Az.DesktopVirtualization\5.4.1\DesktopVirtualization.Autorest\custom\New-AzWvdRegistrationInfo.ps1:99 char:9
+ $hostpool = Az.DesktopVirtualization\New-AzWvdHostPool @PSBou ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : InvalidOperation: ({ }:<>f__AnonymousType1) [New-AzWvdHostPool_CreateExpanded], Exception
+ FullyQualifiedErrorId : 400,Microsoft.Azure.PowerShell.Cmdlets.DesktopVirtualization.Cmdlets.NewAzWvdHostPool_CreateExpanded

ExpirationTime RegistrationTokenOperation Token
-------------- -------------------------- -----
```

### Environment data

```PowerShell
PS C:\Windows\system32> $PSVersionTable

Name Value
---- -----
PSVersion 5.1.22621.4391
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.22621.4391
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
```

### Module versions

```PowerShell
PS C:\Windows\system32> Get-Module Az*

ModuleType Version Name ExportedCommands
---------- ------- ---- ----------------
Script 4.0.2 Az.Accounts {Add-AzEnvironment, Clear-AzConfig, Clear-AzContext, Clear-AzDefault...}
Script 5.4.1 Az.DesktopVirtualization {Disconnect-AzWvdUserSession, Expand-AzWvdMsixImage, Get-AzWvdAppAttachPackage, Get-AzWvdApplication...}
Script 7.9.0 Az.Resources {Export-AzResourceGroup, Export-AzTemplateSpec, Get-AzDenyAssignment, Get-AzDeployment...}
```

### Error output

```PowerShell

```

Start with custom/New-AzWvdRegistrationInfo.ps1, especially the call to New-AzWvdHostPool shown in the stack trace, and inspect how LoadBalancerType values are handled for the Desktop Virtualization API. Confirm the module accepts MultiplePersistent and that New-AzWvdRegistrationInfo works for the described host pool scenario.

Written by the indexing model from the issue text.