feat: support cross-stage data elements in metadata response

[luciano-fiandesio]

Summary

Related Jira Issue: DHIS2-19750

Description

This PR modifies the metadata and headers part of the response for enrollments and events aggregate requests.
When the request contains a dimension like: dimension=A03MvHHogjR.a3kGcGDCuk6 or stage=A03MvHHogjR the metadata and headers now contains the same stage + item reference.

{
  "headers": [
    {
      "name": "pTo4uMt3xur.oZg33kd9taw",
      "column": "Gender",
      "valueType": "TEXT",
      "type": "java.lang.String",
      "hidden": false,
      "meta": true,
      "optionSet": "pC3N9N77UmT"
    },
    ...
  ]
}

"metaData": {
    "pager": {
      ...
    },
    "items": {
      ...
      "pTo4uMt3xur.oZg33kd9taw": {
        "name": "Gender"
      },
    }
}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud