[Bug]: `enabled: false` does not stop OTEL data export

Setting `runtime.telemetry.open-telemetry.enabled` to `false` does not prevent DAB from exporting telemetry data to the OTEL collector.

## Expected

With `enabled: false`, DAB should NOT send any logs, metrics, or traces to the configured OTEL endpoint.

```json
{
"runtime": {
"telemetry": {
"open-telemetry": {
"enabled": false,
"endpoint": "http://localhost:4318",
"service-name": "dab-otel-DISABLED",
"exporter-protocol": "httpprotobuf"
}
}
}
}
```

Expected: Zero OTEL signals received by the collector.

## Actual

After restarting both the OTEL collector (clean state) and DAB (fresh process with `enabled: false`), the collector received logs and metrics from DAB. Three unique `service.instance.id` values confirm three separate DAB processes sent data — including the disabled one.

```powershell
docker logs otel-collector 2>&1 |
Select-String "service.instance.id.*Str" |
ForEach-Object { [regex]::Match($_.Line, 'Str\(([^)]+)\)').Groups[1].Value } |
Sort-Object -Unique

# Output:
# 1375741a-02b3-431a-977c-1e4efc207615 (disabled run)
# 7e2759ce-ca81-4060-a0ef-6705d175caf2 (gRPC run)
# 9abe2ae2-bac1-4581-b1e3-740061d786ac (httpprotobuf run)
```

Latest metric timestamps (`01:02:50 UTC`) postdate the disabled DAB startup, confirming fresh data export.

Inizia dal percorso di configurazione runtime.telemetry.open-telemetry.enabled e riproduci il problema con le impostazioni fornite e un collector OTEL pulito. Traccia dove vengono inizializzati gli exporter di telemetria, quindi verifica che un nuovo processo DAB con enabled impostato su false produca zero log, metriche o trace all’endpoint configurato.

Scritto dal modello di indicizzazione a partire dal testo della issue.