Create data-stream command doesn't create a valid manifest with mappings.subobject = false

[mjwolf]

When creating a new data stream, with the mapping.subobject set to false, the generated manifest will cause an error building the package. There's no error when mappings.subobjects = true. Happens with (at least) elastic-package v0.114.0

Steps to reproduce:

1. Create new datastream by running elastic-package datastream create in a package dir.
2. In the wizard, create "logs" type data-stream and answer "N" to "Enable creation of subobjects for fields with dots in their names?" Give any answer to the other questions.
3. Build the package with elastic-package build. There will be this build error:
   .../data_stream/new_data_stream/manifest.yml" is invalid: field elasticsearch.index_template.mappings: Additional property subobjects is not allowed

This is the manifest file that was created:

title: "New Data Stream"
type: logs
streams:
  - input: logfile
    title: Sample logs
    description: Collect sample logs
    vars:
      - name: paths
        type: text
        title: Paths
        multi: true
        default:
          - /var/log/*.log
elasticsearch:
  index_template:
    mappings:
      subobjects: false