[Stack 8.19.12-SNAPSHOT] [oracle] Failing test daily: system test: (elastic-agent logs - systemstatistics) in oracle.system_statistics

- Stack version: 8.19.12-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.logs2938206222: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-28f70896-e11c-4658-a9c3-14aea09ffc9a (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"
```

Latest issue closed for the same test: https://github.com/elastic/integrations/issues/17919

First build failed: https://buildkite.com/elastic/integrations/builds/40042

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/41254
- https://buildkite.com/elastic/integrations/builds/41263
- https://buildkite.com/elastic/integrations/builds/41308
- https://buildkite.com/elastic/integrations/builds/41368
- https://buildkite.com/elastic/integrations/builds/41411

Start with the failing `system test: (elastic-agent logs - systemstatistics)` for the `oracle.system_statistics` data stream and compare the latest failed Buildkite runs with issue 17919. Check the test logs and Oracle connection setup for the reported `ORA-12541: TNS:no listener`; done means the test passes reliably in the affected builds.

Written by the indexing model from the issue text.