Doppel Integration: Hosted Deployment Issue/ Technical Preview / Beta Version

Hi @efd6 ,

In Ref to PR: https://github.com/elastic/integrations/pull/18777

We've perfomed the testing on Doppel integration and found a couple of issues.

## Issue 1:

We are seeing inconsistent behavior for the Doppel integration between Hosted and Serverless environments.

Findings so far:

- As this integration PR is merged and package is available in EPR: "https://epr.elastic.co/package/doppel/0.1.0/"
- The package manifest includes: https://github.com/elastic/integrations/blob/main/packages/doppel/manifest.yml

```
deployment_modes:
  default:
    enabled: true
```

- In Serverless:

```
  GET kbn:/api/fleet/epm/packages/doppel/0.1.0
```

  returns package metadata successfully.

- In Hosted deployment the same API returns:

```
 {
  "statusCode": 404,
  "error": "Not Found",
  "message": "[doppel] package not installed or found"
}

```
This suggests the package is reachable from Serverless Fleet/EPM but not from Hosted Fleet/EPM.

Could you please help confirm:

1. Whether Hosted deployments use a different package registry/channel/cache than Serverless?
2. Whether beta/prerelease partner integrations ("0.x.x") are filtered or delayed in Hosted Fleet?
3. If there is any additional promotion/sync step required after merge for Hosted visibility?
4. Or do need to make any change in code from our side to make it available in hosted environment?

## Issue 2:

**enable_request_tracer config issue**

- If we explicitly set this value to false, the integration works perfectly.
- If we set it to true (or leave it untouched at its default state), the integration fails with a validation error.

We checked **other** integrations and noticed their enable_request_tracer defaults to false, which is why they work fine out of the box. However, we suspect they will also fail with this validation error(I may be completly wrong here) if a user manually toggles this setting to true in the Fleet UI.

I verified our file path configuration in [stream.yml.hbs](https://github.com/elastic/integrations/blob/a9cfbd711fafda62db9b27f3362faa4afebf3554/packages/doppel/data_stream/alerts/agent/stream/stream.yml.hbs) against [PR #13035](https://github.com/elastic/integrations/pull/13035/changes). The code matches Elastic's updated standards exactly, confirming our integration path is set up correctly.

- Please let us know how we should proceed to fix this validation error. Should we apply a code-level fix, or update our manifest [here](https://github.com/elastic/integrations/blob/a9cfbd711fafda62db9b27f3362faa4afebf3554/packages/doppel/data_stream/alerts/manifest.yml#L62) to default enable_request_tracer to false?
- Or is this a known issue unique to the Serverless environment platform?

Doppel has a significant number of mutual enterprise customers waiting to use this application in production, so we highly appreciate your support in getting this unblocked.

Thank you very much for your help and attention to these issues!

Best,
Bharat k