We know the Dev Team should be self-organising but even then there are guard rails and limits, and a while back there was this related post on hiring https://www.scrum.org/forum/scrum-forum/6071/hiring-and-firing-scrum-team however I didn’t feel it quite produced a clear viewpoint, even if the viewpoint was there isn’t one.
My viewpoint is that an agile leader’s involvement in hiring should be to help a Dev Team with e.g.