Multi-round cleanup

[jmgasper]

Issue 1

We can remove the reminder popup now that we support multiple rounds for design challenges:

Issue 2

From UAT:

For prizes, checkpoint prizes are only $50 or $100 and in general up to 5 max 8, so those textboxes can be much smaller and aligned with the other textfields. “Pay“ can be aligned with “Checkpoint Prizes”