APM logs correlation query missing dataSource for external datasources

[ps48]

Description

• Fixed logs correlation query in the Service Correlations Flyout not including the dataSource field in the dataset config, causing 503 "No Living connections" errors when using external datasources
• The spans query correctly passed dataSource.id but the logs query omitted it, even though dataSourceId was already available from the useCorrelatedLogs hook
• Added unit tests verifying dataSource propagation for both spans and logs queries

Root Cause

In service_correlations_flyout.tsx, the logs dataset config only copied id and title from the correlated log dataset, while the spans dataset config (line 278) correctly included dataSource: { id: datasourceId }. Without dataSource, the PPL query was routed to the local cluster instead of the external datasource.

Issues Resolved

#2545

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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