Update language for Org Admins when they're changing the team lead

[charlesmathias]

Slack link with screenshot 🔒

When an Org Admin edits the Team Lead of a team, they see a message that only makes sense to Team Leads who are giving up their permissions to edit team membership.

I'd suggest "Are you sure? User X will be removed as the team leader and User Y will be promoted. User X will no longer be able to change team membership." The title and CTA for this message can remain the same.

[charlesmathias]

@nickoferrall I think this isn't quite right... See below a gif from the perspective of an Org Admin when they're making themselves a Team lead.

User X: Current Team lead
User Y: New Team lead

Right now, it reads:
"Are you sure? User X will be removed as the team leader and User Y will be promoted. User Y will no longer be able to change team membership."

It should be User X in the last sentence unless User X is an Org Admin. If they are an Org Admin, I propose removing the last sentence.