Update the KQL examples in Discover on the APM advanced queries and Fleet troubleshooting pages for ES|QL mode #9193

Problem

Two pages tell readers to run KQL searches in Discover. {{kib}} now opens Discover in {{esql}} mode by default, so the KQL examples don't match what readers see. Each page needs an {{esql}} path, and each path depends on facts that need checking first.

Pages

• solutions/observability/apm/advanced-queries.md: the "Querying in Discover" section uses KQL queries such as processor.event: "transaction" AND transaction.name: "<TRANSACTION_NAME_HERE>". An {{esql}} path needs the APM data streams to query and equivalent WHERE clauses, and the screenshots show classic mode.
• troubleshoot/ingest/fleet/common-problems.md: a step tells readers to search for service.instance.id: "<your-instance-uid>" in Discover. An {{esql}} path needs the data stream that holds the internal telemetry.

Context

Found while reviewing every docs page that mentions Discover without mentioning {{esql}}, as part of #9190.