Adjust the output of user_agent processor to ECS, part 2

[webmat]

In requesting the adjustments to the user_agent processor (#37329), I made a mistake in one of the field's names.

The desired end result is actually the following:

{
  "name" : "Chrome",
  "original" : "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.102 Safari/537.36",
  "os" : {
    "name" : "Mac OS X",
    "version" : "10.14.1",
    "full" : "Mac OS X 10.14.1"
  },
  "device" : {
    "name": "Other"
  },
  "version" : "70.0.3538.102"
}

Instead of requesting the above, I requested the field "device" as a leaf field (user_agent.device: "foo"). This of course leads to a mapping exception, when outputting the user_agent results in an ECS index.

This nesting of device.name under the object device is there in order to allow for other information about the device eventually (e.g. device.category, device.version, device.manufacturer).

Could we adjust the output of the device name to be at device.name, please?

Really sorry about this!

[elasticmachine]

Pinging @elastic/es-core-features