Update overview.md

[azarboon]

This page is outdated and still refers to Azure AD. I've replaced all references with Entra ID.

[prmerger-automator[bot]]

@azarboon : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[learn-build-service-prod[bot]]

Learn Build status updates of commit 98ced48:

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articles/governance/management-groups/overview.md	:white_check_mark:Succeeded

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[Court72]

@tfitzmac

Can you review the proposed changes?

When the changes are ready for publication, add a #sign-off comment to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged" @MicrosoftDocs/public-repo-pr-review-team

[tfitzmac]

@azarboon - thanks for the update. #sign-off