Bug: Azure Local / Azure Arc Onboarding Stuck – Private Link Scope Network Error

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**Bug description**
I am trying to onboard Azure Local on Azure Arc. The onboarding process gets stuck with the following error message:
```
No indication of Private Link Scope but found private endpoint agentserviceapi.guestconfiguration.azure.com: *.*.*.*
It appears that the process is expecting a Private Link Scope, but the existing scope is deployed in another subscription. This prevents the onboarding from completing.

INFO AZCM0026: Network Error
```
**Repro steps**
Steps to reproduce the behavior:
Start onboarding Azure Local / Azure Stack HCI to Azure Arc.

Follow the onboarding steps until the process checks for Private Link Scope.

Observe that it fails with the above network error.

**Expected behavior**
The onboarding should not ask for a Private Link Scope if the scope is in a different subscription. The process should either:

Allow cross-subscription scopes, or

Skip the Private Link requirement when no scope exists in the current subscription.

**Environment (please complete the following information):**

Agent Version : 1.55.03132.2414
Agent Logfile : C:\ProgramData\AzureConnectedMachineAgent\Log\himds.log
Agent Status : Disconnected
Agent Last Heartbeat :
Agent Error Code :
Agent Error Details :
Agent Error Timestamp :
Using HTTPS Proxy :
Proxy Bypass List :
Upstream Proxy :
Gateway URL :
Cloud Provider : AzSHCI
Cloud Metadata
Manufacturer : HPE
Model : ProLiant DL380 Gen10 Plus

**Screenshots**

Azure Local / Azure Arc のオンボーディングを Private Link Scope のチェックまで再現し、C:\\ProgramData\\AzureConnectedMachineAgent\\Log\\himds.log を調べて AZCM0026 の失敗を確認する。別のサブスクリプションにある scope がサポートされるのか、またはスキップすべきなのかを判断する。オンボーディングがこのネットワークエラーなしで完了すれば完了とする。

索引モデルが issue の本文から書いたものです。