Add note about indirect membership on the expiration warning

When warning somebody about a membership which is going to expire, it'd be nice to add a note saying something like

"You will, however, continue to be active in this team thanks to your memberships in foo, bar and baz which are themselves part of the xxx team."

when the member is also an indirect member of that team.

This can also be shown when a team admin removes a member from a given team but that person is also an indirect member of that team.