Update microsoft-network-expressroutegateways-metrics.md

[shyambasnet1]

We are adding a scale unit metric

[prmerger-automator]

@shyambasnet1 : 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 c392fb6:

✅ Validation status: passed

File	Status	Preview URL	Details
articles/azure-monitor/reference/supported-metrics/microsoft-network-expressroutegateways-metrics.md	✅Succeeded

For more details, please refer to the build report.

[v-regandowner]

@bwren

Can 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 at least 14 days. If you are finished with your changes, don't forget to sign off. See the contributor guide for instructions.
Get Help
Docs Support Teams Channel
Resolve Merge Conflict

[prmerger-automator]

@shyambasnet1 : Thanks for your contribution! The author(s) and reviewer(s) have been notified to review your proposed change.

[v-dirichards]

@asudbring

Can you review this old PR and determine whether it needs to be closed or merged?

@MicrosoftDocs/public-repo-pr-review-team

[github-actions]

This pull request has been inactive for at least 14 days. If you are finished with your changes, don't forget to sign off. See the contributor guide for instructions.
Get Help
Docs Support Teams Channel
Resolve Merge Conflict