fix(specs): partial update operation (generated)

algolia/api-clients-automation#3486

Co-authored-by: algolia-bot <accounts+algolia-api-client-bot@algolia.com>
Co-authored-by: Kai Welke <kai.welke@algolia.com>
Co-authored-by: shortcuts <vannicattec@gmail.com>
Co-authored-by: Pierre Millot <pierre.millot@algolia.com>