Update integration package to package spec v3

[axw]

elastic/package-spec#539

We should also add "apm" (and "observability"?) as a required capability for installing the package. See https://github.com/elastic/package-spec/blob/889754b93f7ee6f48651630dc4315cc59d43ec3b/spec/integration/manifest.spec.yml#L104-L119

[kyungeunni]

This is currently blocked by this ticket. For the timebeing, it can be unblocked if the package-spec allows us to specify the mapping definition that has dynamic property in the manifest.yml, at least until we have the proper fix.

Before migrating, the following mapping was added to the template:

  "labels": {
    "type": "object",
    "dynamic": "true"
  },
  "numeric_labels": {
    "type": "object",
    "dynamic": "true"
  },

But with the latest version, it doesn't add this but only creates the dynamic_templates and it's causing an error like this:

.ds-metrics-apm.transaction.1m-default-2023.10.24-000001' (illegal_state_exception): Missing intermediate object numeric_labels"

cc @jsoriano @simitt

[kyungeunni]

It's unblocked thanks to the Fleet change: elastic/kibana#169981

[kyungeunni]

Mark it as blocked as we are depending on the Kibana snapshot that contains the change

[kyungeunni]

#11822 is ready for reviews.