Update service limits for email recipient count for SMTP

[ealmuneyeer]

Remove the note stating that the number of recipients for SMTP cannot exceed 50, as the increment is now supported

[prmerger-automator]

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

[learn-build-service-prod]

Learn Build status updates of commit 750ed8a:

✅ Validation status: passed

File	Status	Preview URL	Details
articles/communication-services/concepts/service-limits.md	✅Succeeded

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[Copilot]

Pull request overview

This PR updates the documentation to reflect that SMTP email sending now supports more than 50 recipients, removing outdated limitations that previously stated this feature was not supported.

Key Changes:

• Removed statement indicating SMTP cannot send to more than 50 recipients
• Removed note stating quota increase requests for SMTP recipient count are not supported

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[prmerger-automator]

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

[ttorble]

@sroons

Can you review the proposed changes?

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#label:"aq-pr-triaged"
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