Update admin-controlled-migration-policy.md

[caithart]

Removed a blurb with some inaccuracies and referred instead to the longer article just published that elaborates on the topic of monitoring usage.

[learn-build-service-prod]

Learn Build status updates of commit cecf6ff:

💡 Validation status: suggestions

File	Status	Preview URL	Details
microsoft-365-apps/outlook/manage/admin-controlled-migration-policy.md	💡Suggestion		Details

microsoft-365-apps/outlook/manage/admin-controlled-migration-policy.md

• Line 233, Column 95: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://learn.microsoft.com/microsoft-365-apps/outlook/manage/monitor-usage-reports' will be broken in isolated environments. Replace with a relative link.

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[nicholasswhite]

Moved to private repo per: https://github.com/MicrosoftDocs/OfficeDocs-DeployOffice-pr/pull/3824