[LogsDB] [Stack 8.19.17-SNAPSHOT] [oracle] Failing test daily: system test: (elastic-agent logs - sysmetric) in oracle.sysmetric

- Stack version: 8.19.17-SNAPSHOT
- LogsDB: enabled
- Package: oracle
- Failing test: system test: (elastic-agent logs - sysmetric)
- DataStream: sysmetric
- Owners:
- @elastic/obs-infraobs-integrations

Failure:
```
test case failed: one or more errors found while examining elastic-agent.logs3679617964: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-99bfc8fc-2eec-4478-805d-5bbf3bad134f (HEALTHY->DEGRADED): Error fetching data for metricset sql.query: cannot open connection: testing connection: user=\"sys\" standalone params={authMode:2 connectionClass: connectionClassLength:0 purity:0 newPassword: newPasswordLength:0 appContext: numAppContext:0 externalAuth:0 externalHandle: pool: tag: tagLength:0 matchAnyTag:0 outTag: outTagLength:0 outTagFound:0 shardingKeyColumns: numShardingKeyColumns:0 superShardingKeyColumns: numSuperShardingKeyColumns:0 outNewSession:0}: ORA-12541: TNS:no listener"
```

First build failed: https://buildkite.com/elastic/integrations/builds/45080

Latest failed builds:
- https://buildkite.com/elastic/integrations/builds/45168

Start with the failing Oracle sysmetric system test and the linked Buildkite failures, then trace the elastic-agent logs output for the ORA-12541 error. Check whether the Oracle listener or test environment is unavailable and confirm the test passes reliably without the connection failure.

Written by the indexing model from the issue text.