Update manage-rbac.md

[YulelogPagoda]

Added information to let people know that the Device Group permissions that used to exist in Roles now has been moved to Device Groups.

[learn-build-service-prod]

Learn Build status updates of commit 419091a:

✅ Validation status: passed

File	Status	Preview URL	Details
defender-xdr/manage-rbac.md	✅Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[learn-build-service-prod]

Learn Build status updates of commit 8eea787:

✅ Validation status: passed

File	Status	Preview URL	Details
defender-xdr/manage-rbac.md	✅Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[diannegali]

reviewed