[APM] Service maps: anomaly stats for service node are not cleared

[dgieselaar]

When getting new data for the service map, anomaly stats for a service node are not cleared if the new response doesn't return any anomaly stats for that node. To reproduce:

• Go to an opbeans environment with ML enabled and navigate to the global service map
• Notice that opbeans-java has anomaly stats for the production environment
• Select testing as the environment
• Notice from the API response that no anomaly stats are returned for opbeans-java, but are still displayed in the browser
• Refresh the page for the same URL and notice that no anomaly stats are shown for opbeans-java (this is correct)

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[botelastic[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[akhileshpok]

@dgieselaar - What is the impact of this issue on users? Thanks

[dgieselaar]

@akhileshpok if users select a different time range, a service might still display as unhealthy even though it was not unhealthy for that time range.