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

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

Failure:
```
test case failed: one or more errors found while examining elastic-agent.logs2873330601: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-d9649241-2d21-4a47-b05e-14b569e62966 (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 - memory` system test for the `oracle.memory` data stream and inspect the linked Buildkite failures, especially the ORA-12541 `TNS:no listener` error. Done means the test completes successfully without the Oracle connection entering a degraded state.

Written by the indexing model from the issue text.