[Stack 9.4.0-SNAPSHOT] [nats] Failing test daily: system test: default (variant: v2) in nats.connection

- Stack version: 9.4.0-SNAPSHOT
- Package: nats
- Failing test: system test: default (variant: v2)
- DataStream: connection
- Owners:
- @elastic/obs-infraobs-integrations

Error:
```
failed to search docs for data stream metrics-nats.connection-83015: [500 Internal Server Error] {"error":{"root_cause":[{"type":"array_index_out_of_bounds_exception","reason":"Index 28 out of bounds for length 28"}],"type":"search_phase_execution_exception","reason":"all shards failed","phase":"query","grouped":true,"failed_shards":[{"shard":0,"index":".ds-metrics-nats.connection-83015-2026.03.26-000001","node":"vUCIJZ8fSf20njPUO_YVEA","reason":{"type":"array_index_out_of_bounds_exception","reason":"Index 28 out of bounds for length 28"}}],"caused_by":{"type":"array_index_out_of_bounds_exception","reason":"Index 28 out of bounds for length 28","caused_by":{"type":"array_index_out_of_bounds_exception","reason":"Index 28 out of bounds for length 28"}}},"status":500}
```

First build failed: https://buildkite.com/elastic/integrations/builds/40342