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

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

Failure:
```
test case failed: one or more errors found while examining elastic-agent.logs984054944: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-50403109-607a-4125-aa0a-a9da9a682b70 (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 `elastic-agent logs - systemstatistics` system test for the `oracle.system_statistics` data stream and review the failure in builds 45080 and 45168. Investigate the reported ORA-12541 no-listener error and the Oracle test connection; done means the test completes without the metricset entering a degraded state.

Written by the indexing model from the issue text.