Has anyone else had a SideShift gig ask you to do anything through apples “TestFlight” program?

I’ve finally started getting responses after a while of applying to stuff on side shift and this one I’m working with is asking me to get an app through TestFlight and get a subscription(TestFlight is sandbox so it’s not real money being used) to use a tool I’ll be promoting, but I can’t use Face ID for sandbox purchases in TestFlight, for some reason, and it wants my regular Apple ID password, what are the odds that it’s fake and they’re just trying to steal my info?