I had originally put the limit in place after observing too many novice players unwittingly saving screenshots to the MachineProfile, but things have changed since then.

Casual GameMode doesn't allow screenshots at all, and competitive players may very well want more than one screenshot of ScreenEvaluation now that there are multiple panes of information.

This commit also speeds up the ScreenShot animation.  4 seconds was too long; 1.5 feels better and is less likely to cause issues with a second screenshot being obscured by part of the first screenshot's animation(!).