Correct NSG rules for DocumentDB connection troubleshooting

[jasonhumsft]

The port is wrong, and the subnet of private endpoint should allow inbound connectivity instead of outbound.

Reference document: https://learn.microsoft.com/en-us/azure/documentdb/troubleshoot-common-issues#debugging-connectivity-issues

[prmerger-automator]

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

[learn-build-service-prod]

Learn Build status updates of commit 9f8ff49:

✅ Validation status: passed

File	Status	Preview URL	Details
articles/documentdb/how-to-private-link.md	✅Succeeded

For more details, please refer to the build report.

[ShannonLeavitt]

@khelanmodi - Could you review the proposed changes?

IMPORTANT: When the changes are ready for publication, adding a #sign-off comment is the best way to signal that the PR is ready for the review team to merge.

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

[github-actions]

This pull request has been inactive for 14 days. If you are finished with your changes, don't forget to sign off. See the contributor guide for instructions. If this PR is inactive for 14 more days, it will be closed automatically. Thank you!
SQL Docs Team: Contact Us
Contributor Guide

[github-actions]

This pull request has been inactive for 28 days. At this time, we are closing the PR. If you decide to continue working on your change, you can reopen the PR and continue working. Thank you!

SQL Docs Team: Contact Us
Contributor Guide