Reverse the order of the Training Requests "membership seats" dropdown

[froggleston]

In the Training Requests screen, e.g. https://amy.carpentries.org/requests/training_requests/, when matching an unmatched individual to a member organisation membership, the Membership Seats dropdown is ordered from the oldest at the top to the most recent at the bottom. This means we often have to scroll to get to the option we would like.

Could this dropdown ordering be reversed so the most recent dated memberships are at the top?