[Bug] Elastic Agent Metricbeat Data Stream incorrectly maps `network` field as a `keyword` rather than an `object`

Elastic Agent 7.14.0 Metircbeat Data Stream incorrectly maps the `network` field as a `keyword`, rather than an `object` as specified by [ECS](https://www.elastic.co/guide/en/ecs/1.11/ecs-network.html)

This is causing an issue in Kibana as its causing a mapping conflict within the Kibana Index Pattern `logs-*`

Example:

`GET /.ds-logs-elastic_agent.metricbeat-dev-2021.08.25-000001/_mapping/field/network`

```json
{
".ds-logs-elastic_agent.metricbeat-dev-2021.08.25-000001" : {
"mappings" : {
"network" : {
"full_name" : "network",
"mapping" : {
"network" : {
"type" : "keyword",
"ignore_above" : 1024
}
}
}
}
}
}
```