managedDeviceCleanupSettings on DeviceManagement entity should be a navigation property instead of a property (Get-MgBetaDeviceManagement - Missing value for DeviceInactivityBeforeRetirementInDays)

Describe the bug
When executing the Get-MgBetaDeviceManagement cmdlet and accessing the ManagedDeviceCleanupSettings object, the value for the inner property DeviceInactivityBeforeRetirementInDays is null. Calling the Graph API with Invoke-MgGraphRequest -Uri https://graph.microsoft.com/beta/deviceManagement/ManagedDeviceCleanupSettings returns the correct value for the property.

To Reproduce
Steps to reproduce the behavior:

1. Execute Get-MgBetaDeviceManagement and filter for the ManagedDeviceCleanupSettings object:
   (Get-MgBetaDeviceManagement).ManagedDeviceCleanupSettings
2. See the empty value for the DeviceInactivityBeforeRetirementInDays property.

Expected behavior
It should display the same output as with Invoke-MgGraphRequest.

Debug Output

> (Get-MgBetaDeviceManagement -Debug).ManagedDeviceCleanupSettings
DEBUG: [CmdletBeginProcessing]: - Get-MgBetaDeviceManagement begin processing with parameterSet 'Get'.  

Confirm
Continue with this operation?
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DEBUG: [Authentication]: - AuthType: 'AppOnly', TokenCredentialType: 'ClientSecret', ContextScope: 'Process', AppName: 'graphpowershell'.
DEBUG: [Authentication]: - Scopes: [Directory.Read.All, DeviceManagementServiceConfig.ReadWrite.All, DeviceManagementManagedDevices.ReadWrite.All,
DeviceManagementConfiguration.ReadWrite.All, DeviceManagementApps.ReadWrite.All].
DEBUG: ============================ HTTP REQUEST ============================

HTTP Method:
GET

Absolute Uri:
https://graph.microsoft.com/beta/deviceManagement

Headers:
FeatureFlag                   : 00000043
Cache-Control                 : no-store, no-cache
User-Agent                    : Mozilla/5.0,(Windows NT 10.0; Microsoft Windows 10.0.22621; de-CH),PowerShell/5.1.22621.2428
Accept-Encoding               : gzip
SdkVersion                    : graph-powershell-beta/2.6.1
client-request-id             : 26166a23-6705-4aa9-abf4-26345929a586

Body:


DEBUG: ============================ HTTP RESPONSE ============================

Status Code:
OK

Headers:
Transfer-Encoding             : chunked
Vary                          : Accept-Encoding
Strict-Transport-Security     : max-age=31536000
request-id                    : 8d806fc3-3801-4bcf-b9b1-4a91c7e246af
client-request-id             : 26166a23-6705-4aa9-abf4-26345929a586
x-ms-ags-diagnostic           : {"ServerInfo":{"DataCenter":"North Europe","Slice":"E","Ring":"4","ScaleUnit":"004","RoleInstance":"DB1PEPF0001F9D8"}}
OData-Version                 : 4.0
Date                          : Tue, 17 Oct 2023 13:05:47 GMT

Body:
{
  "@odata.context": "https://graph.microsoft.com/beta/$metadata#deviceManagement",
  "id": "deviceManagement",
  "settings": null,
  "maximumDepTokens": 100,
  "intuneAccountId": "23c03e74-487d-473e-bbde-12141ce45bbb",
  "lastReportAggregationDateTime": "0001-01-01T00:00:00Z",
  "deviceComplianceReportSummarizationDateTime": "0001-01-01T00:00:00Z",
  "legacyPcManangementEnabled": false,
  "unlicensedAdminstratorsEnabled": true
}

DEBUG: [CmdletEndProcessing]: - Get-MgBetaDeviceManagement end processing.

DeviceInactivityBeforeRetirementInDays
--------------------------------------

Module Version

> Get-Module Microsoft.Graph.Beta.Devicemanagement

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Script     2.6.1      Microsoft.Graph.Beta.DeviceManag... {Get-MgBetaAdminEdge, Get-MgBetaAdminEdgeInternetExplorerM...

Environment Data

 $PSVersionTable

Name                           Value
----                           -----
PSVersion                      5.1.22621.2428
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.22621.2428
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Screenshots

Additional context

Add any other context about the problem here.

Start by comparing the DeviceManagement metadata for managedDeviceCleanupSettings with the Graph endpoint shown in the report: https://graph.microsoft.com/beta/deviceManagement/ManagedDeviceCleanupSettings. Confirm that DeviceInactivityBeforeRetirementInDays is exposed through the generated navigation relationship, then verify that Get-MgBetaDeviceManagement matches Invoke-MgGraphRequest.