Get-AzManagementGroup -> Value cannot be null. (Parameter 'g')

### Description

Getting new error, not sure how to get past it:
$managementGroups = Get-AzManagementGroup
| ~~~~~~~~~~~~~~~~~~~~~
| Value cannot be null. (Parameter 'g')

### Issue script & Debug output

```PowerShell
$managementGroups = Get-AzManagementGroup
DEBUG: Initializing ConditionalAssemblyContext. PSEdition is [Core]. PSVersion is [7.5.0].
DEBUG: Initializing ConditionalAssemblyProvider. AssemblyRootPath is [/Users/jasonbreetz/.local/share/powershell/Modules/Az.Accounts/4.0.2/StartupScripts/../lib].
DEBUG: Registering Az shared AssemblyLoadContext.
DEBUG: AssemblyLoadContext registered.
DEBUG: Initializing PSStyle.
DEBUG: Got version 0 of Az
DEBUG: Got version 0 of Az.Accounts
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [DisplaySecretsWarning], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:29:20 AM - GetAzureRmManagementGroup begin processing with ParameterSet 'ListOperation'.
DEBUG: 11:29:20 AM - using account id 'JasonBreetz@EntroSecEngineering.onmicrosoft.com'...
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [DisplayBreakingChangeWarning], Module = [Az.Resources], Cmdlet = [Get-AzManagementGroup]. Returning default value [True].
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [EnableErrorRecordsPersistence], Module = [Az.Resources], Cmdlet = [Get-AzManagementGroup]. Returning default value [False].
Get-AzManagementGroup: Value cannot be null. (Parameter 'g')
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [DisplayBreakingChangeWarning], Module = [Az.Resources], Cmdlet = [Get-AzManagementGroup]. Returning default value [True].
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [DisplayRegionIdentified], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [CheckForUpgrade], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: AzureQoSEvent: Module: Az.Resources:7.8.1; CommandName: Get-AzManagementGroup; PSVersion: 7.5.0; IsSuccess: False; Duration: 00:00:00.0683252; SanitizeDuration: 00:00:00; Exception: Value cannot be null. (Parameter 'g');
DEBUG: 11:29:20 AM - [ConfigManager] Got nothing from [EnableDataCollection], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:29:20 AM - GetAzureRmManagementGroup end processing.
```

### Environment data

```PowerShell
Name Value
---- -----
PSVersion 7.5.0
PSEdition Core
GitCommitId 7.5.0
OS Darwin 24.3.0 Darwin Kernel Version 24.3.0: Thu Jan 2 20:23:36 PST 2025; root:xnu-11215.81.4~3/RELEASE_A…
Platform Unix
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 ExportedCommands
---------- ------- ---------- ---- ----------------
Script 4.0.2 Az.Accounts {Add-AzEnvironment, Clear-AzConfig, Clear-AzContext, Clear-AzDefaul…
Script 7.8.1 Az.Resources {Export-AzResourceGroup, Export-AzTemplateSpec, Get-AzDenyAssignmen…
```

### Error output

```PowerShell
DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [DisplaySecretsWarning], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:31:44 AM - ResolveError begin processing with ParameterSet 'AnyErrorParameterSet'.
DEBUG: 11:31:44 AM - using account id 'JasonBreetz@EntroSecEngineering.onmicrosoft.com'...
DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [DisplayBreakingChangeWarning], Module = [Az.Accounts], Cmdlet = [Resolve-AzError]. Returning default value [True].
DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [DisplaySecretsWarning], Module = [], Cmdlet = []. Returning default value [True].

HistoryId: 3

Message : Value cannot be null. (Parameter 'g')
StackTrace : at System.ArgumentNullException.Throw(String paramName)
at System.Guid..ctor(String g)
at Microsoft.Azure.Commands.Common.Authentication.Factories.AuthenticationFactory.GetServiceClientCredentials(IAzureC
ontext context, String targetEndpoint, String resourceId)
at Microsoft.Azure.Commands.Common.Authentication.Factories.AuthenticationFactory.GetServiceClientCredentials(IAzureC
ontext context, String targetEndpoint)
at Microsoft.Azure.Commands.Common.Authentication.Factories.ClientFactory.CreateArmClient[TClient](IAzureContext
context, String endpoint)
at Microsoft.Azure.Commands.Resources.ManagementGroups.Common.AzureManagementGroupsCmdletBase.get_ManagementGroupsApi
Client()
at Microsoft.Azure.Commands.Resources.ManagementGroups.GetAzureRmManagementGroup.ExecuteCmdlet()
at Microsoft.WindowsAzure.Commands.Utilities.Common.CmdletExtensions.<>c__3`1.b__3_0(T
c)
at Microsoft.WindowsAzure.Commands.Utilities.Common.CmdletExtensions.ExecuteSynchronouslyOrAsJob[T](T cmdlet,
Action`1 executor)
at Microsoft.WindowsAzure.Commands.Utilities.Common.CmdletExtensions.ExecuteSynchronouslyOrAsJob[T](T cmdlet)
at Microsoft.WindowsAzure.Commands.Utilities.Common.AzurePSCmdlet.ProcessRecord()
Exception : System.ArgumentNullException
InvocationInfo : {Get-AzManagementGroup}
Line : $managementGroups = Get-AzManagementGroup
Position : At line:1 char:25
+ $managementGroups = Get-AzManagementGroup
+ ~~~~~~~~~~~~~~~~~~~~~
HistoryId : 3

DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [DisplayRegionIdentified], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [CheckForUpgrade], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: AzureQoSEvent: Module: Az.Accounts:4.0.2; CommandName: Resolve-AzError; PSVersion: 7.5.0; IsSuccess: True; Duration: 00:00:00.0172944; SanitizeDuration: 00:00:00.0028980
DEBUG: 11:31:44 AM - [ConfigManager] Got nothing from [EnableDataCollection], Module = [], Cmdlet = []. Returning default value [True].
DEBUG: 11:31:44 AM - ResolveError end processing.
```

Start by reproducing Get-AzManagementGroup with the PowerShell 7.5.0 and Az module versions shown. Trace the stack from GetAzureRmManagementGroup through ManagementGroupsCmdletBase.ManagementGroupsApi, ClientFactory.CreateArmClient, and AuthenticationFactory.GetServiceClientCredentials; done means the command no longer throws ArgumentNullException for parameter 'g'.

Written by the indexing model from the issue text.