Updated structure and content for latency probe metric

[prmerger-automator[bot]]

@sujamiya : 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 1c40e3f:

:white_check_mark: Validation status: passed

File	Status	Preview URL	Details
articles/firewall/monitor-firewall-reference.md	:white_check_mark:Succeeded

For more details, please refer to the build report.

For any questions, please:

• Try searching the learn.microsoft.com contributor guides
• Post your question in the Learn support channel

[ShannonLeavitt]

@sujamiya - FTEs need to work in the private repo, not here in the public repo. Please see this reference to move your commits to the private repo.