Update requirements for using @mentions in Notes

[robertoilidio]

Clarified requirements for using @mentions in Notes, specifically including enabling Dynamics 365 apps during environment provisioning as requirement.

[learn-build-service-prod]

Learn Build status updates of commit 3803e83:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
powerapps-docs/user/use-@mentions.md	⚠️Warning		Details

powerapps-docs/user/use-@mentions.md

• Line 26, Column 408: [Warning: hard-coded-locale - See documentation] Link 'https://learn.microsoft.com/en-us/power-platform/admin/create-environment#some-important-considerations-when-creating-a-new-environment' contains locale code 'en-us'. For localizability, remove 'en-us' from links to most Microsoft sites.
• Line 26, Column 408: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://learn.microsoft.com/en-us/power-platform/admin/create-environment#some-important-considerations-when-creating-a-new-environment' will be broken in isolated environments. Replace with a relative link.

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