[Core Telemetry] Add more memory indicators

[afharo]

Summary

Resolves #100532

Checklist

• [x] Unit or functional tests were updated or added to match the most common scenarios

For maintainers

• [x] This was checked for breaking API changes and was labeled appropriately

[afharo]

/ci

[afharo]

/ci

[afharo]

/ci

[kibana-ci]

:yellow_heart: Build succeeded, but was flaky

• Buildkite Build
• Commit: ec29e5a216127a850c3f976a313a039848bd9bf1

Failed CI Steps

• FTR Configs #5

Metrics [docs]

✅ unchanged

History

• :broken_heart: Build #208515 failed 469ddfe2fa5a4c8fb283b919f01625f023ef825c
• :broken_heart: Build #208500 failed 135ac3da504caffb25583c2999078e1747c51945

To update your PR or re-run it, just comment with: @elasticmachine merge upstream

cc @afharo

[elasticmachine]

Pinging @elastic/kibana-core (Team:Core)