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

- Stack version: 8.19.18-SNAPSHOT
- Package: oracle
- Failing test: system test: (elastic-agent logs - sysmetric)
- DataStream: sysmetric
- Owners:
- @elastic/obs-infraobs-integrations

Failure:
```
test case failed: one or more errors found while examining elastic-agent.logs1921285987: [0] found error "Unit state changed sql/metrics-default-sql/metrics-oracle-9f0acace-0967-49cc-a230-bb250453367f (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/45218

Latest 5 failed builds:
- https://buildkite.com/elastic/integrations/builds/45763
- https://buildkite.com/elastic/integrations/builds/45841
- https://buildkite.com/elastic/integrations/builds/45909
- https://buildkite.com/elastic/integrations/builds/45972
- https://buildkite.com/elastic/integrations/builds/46036

Start by reviewing the latest failed Buildkite runs for the Oracle `sysmetric` system test and its `elastic-agent.logs` output. Investigate the `sql.query` connection failure reporting `ORA-12541: TNS:no listener`; done means the test passes without the agent entering a degraded state.

Written by the indexing model from the issue text.