Add departmental billing section to backup-billing.md

[GreenOutside]

Added a section on departmental billing for Microsoft 365 Backup, outlining its benefits, setup process, and management of billing policies.

[github-actions]

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[learn-build-service-prod]

Learn Build status updates of commit 1915967:

⚠️ Validation status: warnings

File	Status	Preview URL	Details
microsoft-365/backup/backup-billing.md	⚠️Warning		Details

microsoft-365/backup/backup-billing.md

• Line 62, Column 1: [Warning: multiple-h1s - See documentation] Multiple H1s(H1 'Manage consumption and invoices for Microsoft 365 Backup') are not allowed. You can only have one top-level heading.
• Line 38, Column 52: [Suggestion: duplicate-alt-text - See documentation] Alt text 'image' is duplicated. Within an article, alt text must be unique.
• Line 42, Column 67: [Suggestion: docs-link-absolute - See documentation] Absolute link 'https://learn.microsoft.com/microsoft-365/backup/backup-setup?view=o365-worldwide#2-create-backup-policies-to-protect-your-data' will be broken in isolated environments. Replace with a relative link.
• Line 42, Column 67: [Suggestion: preserve-view-not-set - See documentation] You've pinned this link to a specific version of content with the view parameter. It's recommended not to pin a version unless that version is A) not the default view and B) the context is about that version specifically. To proceed with pinning a version add the &preserve-view=true to the URL. Otherwise, remove the view parameter. URL: https://learn.microsoft.com/microsoft-365/backup/backup-setup?view=o365-worldwide#2-create-backup-policies-to-protect-your-data
• Line 44, Column 52: [Suggestion: duplicate-alt-text - See documentation] Alt text 'image' is duplicated. Within an article, alt text must be unique.
• Line 51, Column 48: [Suggestion: duplicate-alt-text - See documentation] Alt text 'image' is duplicated. Within an article, alt text must be unique.
• Line 57, Column 56: [Suggestion: duplicate-alt-text - See documentation] Alt text 'image' is duplicated. Within an article, alt text must be unique.

For more details, please refer to the build report.

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