Merge branch 'md-rest-api-time-tracking-endpoint-validation' into 'master'

Add non negative validation to update time estimate rest api endpoint

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/126620



Merged-by: Heinrich Lee Yu <heinrich@gitlab.com>
Approved-by: Marco Zille <marco.zille@gmail.com>
Approved-by: Gregorius Marco <gmarco@gitlab.com>
Approved-by: Heinrich Lee Yu <heinrich@gitlab.com>
Reviewed-by: Marco Zille <marco.zille@gmail.com>
Reviewed-by: Gregorius Marco <gmarco@gitlab.com>
Co-authored-by: Missy Davies <ms.melissadavies@gmail.com>