Update Feature Anywhere documentation to explicitly call out what types of anomaly results are supported

[ohltyler]

Currently, only real-time, single-entity results are supported and visible on OSD Visualizations for linked detectors. This documentation should be updated to explicitly call that out.

Depending on when this proposed enhancement in AD to support historical results is completed, this will need to be updated once more.

[hdhalter]

Thanks, @ohltyler. Can you help updating with the appropriate documentation? https://github.com/opensearch-project/documentation-website/edit/main/_observing-your-data/ad/dashboards-anomaly-detection.md

[ohltyler]

Thanks, @ohltyler. Can you help updating with the appropriate documentation? https://github.com/opensearch-project/documentation-website/edit/main/_observing-your-data/ad/dashboards-anomaly-detection.md

updated in #7663 :)