Add borders to images in the "Collect Metrics from Azure Monitor" article

[jpipkin1]

Purpose of this pull request

This pull request adds borders to images in this article:
https://help.sumologic.com/docs/send-data/collect-from-other-data-sources/azure-monitoring/collect-metrics-azure-monitor/

Select the type of change

• Minor Changes - Typos, formatting, slight revisions
• Update Content - Revisions, updating sections
• New Content - New features, sections, pages, tutorials
• Site and Tools - .clabot, version updates, maintenance, dependencies, new packages for the site (Docusaurus, Gatsby, React, etc.)

Ticket (if applicable)

NA