Update Uninstall-ADServiceAccount.md

[HerbertMauerer]

PR Summary

add Name uniqueness warning
remove rodc reference, you can run this one on RODC

PR Checklist

• Descriptive Title: Small updates on name and RODC use.
• Summary: We learned that at samAccountName needs to be unique in the forest for GMSA, and this cmdlet can be run on RODC
• Contributor's Guide: I have read the contributors guide.
• Style: This PR adheres to the style guide.

[learn-build-service-prod]

Learn Build status updates of commit ae07fbd:

✅ Validation status: passed

File	Status	Preview URL	Details
docset/winserver2022-ps/activedirectory/Uninstall-ADServiceAccount.md	✅Succeeded	View (WindowsServer2022-ps)

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