🐛 API spec for extraction pipeline (#1981)

# Description

Small bug in the YAML spec for extraction pipelines

## Changelog

- [x] Patch
- [ ] Skip

## cdf

### Fixed

- When running `cdf build` Toolkit no longer give warnings on extraction
pipelines for unused field sendNotification. For example: ` In
contacts[1] unused field: 'sendNotification'`

## templates

No changes.
