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

- Stack version: 8.19.20-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.logs796310524: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-7fd5406f-6b76-4b88-bf4a-3783d164716c (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/47076

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/48320
- https://buildkite.com/elastic/integrations/builds/48399
- https://buildkite.com/elastic/integrations/builds/48456
- https://buildkite.com/elastic/integrations/builds/48531
- https://buildkite.com/elastic/integrations/builds/48613

Start with the latest failed build and the oracle.memory system test output; investigate why the Oracle listener is unavailable when the sql.query metricset connects. Done means the elastic-agent logs memory test passes in the Oracle environment without the ORA-12541 failure.

Written by the indexing model from the issue text.