[Stack 8.19.20-SNAPSHOT] [oracle] Failing test daily: system test: (elastic-agent logs - systemstatistics) in oracle.system_statistics

- Stack version: 8.19.20-SNAPSHOT
- 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.logs2258683130: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-6b214a3f-1bec-4e24-a793-4dd208f83a5d (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/47075

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/48319
- https://buildkite.com/elastic/integrations/builds/48398
- https://buildkite.com/elastic/integrations/builds/48455
- https://buildkite.com/elastic/integrations/builds/48532
- https://buildkite.com/elastic/integrations/builds/48614

Start with the oracle.system_statistics system test and the elastic-agent logs from the linked Buildkite failures, focusing on the ORA-12541 no-listener error during the sql.query metricset connection. Reproduce or trace the failure in the latest integration build, then verify that the Oracle system test passes without the connection error across subsequent builds.

Written by the indexing model from the issue text.