[LogsDB] [Stack 8.19.18-SNAPSHOT] [oracle] Failing test daily: system test: (elastic-agent logs - memory) in oracle.memory

- Stack version: 8.19.18-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.logs3493729794: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-004f7cd2-83d2-417b-b197-78689831aca8 (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/45219

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/45764
- https://buildkite.com/elastic/integrations/builds/45840
- https://buildkite.com/elastic/integrations/builds/45910
- https://buildkite.com/elastic/integrations/builds/45971
- https://buildkite.com/elastic/integrations/builds/46035

Start with the oracle.memory system test and compare the logs from the five latest failed Buildkite builds, focusing on the ORA-12541 no-listener error while collecting the memory data stream. Identify why the Oracle connection is unavailable and verify that the test passes in subsequent integrations builds.

Written by the indexing model from the issue text.