Show Pro Confilicts

Right now, I can book the same pro multiple times at the same time for different lessons.  Would be nice if this showed as a "conflict" like it does when we book the same court multiple times for different people.  It doesn't necessarily have to not allow it, just to flag it, so we know or have an option to not allow it at all or to allow it, but flag it.

As we decide if we will use this in our busy summer season, it's crucial that we have this safeguard as we have many high school staffers who we need to make it easy to not mess up.