Merge branch 'mallocke/remove_is_todo_kwarg' into 'master'

Remove first_line_in_markdown is_todo kwarg

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/149193



Merged-by: Justin Ho Tuan Duong <hduong@gitlab.com>
Approved-by: Madelein van Niekerk <mvanniekerk@gitlab.com>
Approved-by: Justin Ho Tuan Duong <hduong@gitlab.com>
Approved-by: Aaron Huntsman <ahuntsman@gitlab.com>
Co-authored-by: Malcolm Locke <mlocke@gitlab.com>