DOCS-1701 - Update disabled metrics sources doc to reflect improved source pausing logic

[amee-sumo]

Purpose of this pull request

Updates docs/metrics/manage-metric-volume/disabled-metrics-sources.md to clarify the improved source pausing logic: Sumo Logic now disables metric sources based on cardinality growth (comparing the most recent 7-day period against the prior 7-day period) rather than targeting the sources with the highest current cardinality. Sources that have recently grown and contributed to the breach are paused first, while stable high-volume sources are left unaffected.

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)

https://sumologic.atlassian.net/browse/DOCS-1701