SSP-2857 remove hasWatchStudent dependency on PersonSearchDao

myWatchList and myCaseload interfere with each other.  myCaseload takes precedence.  Code update now respects both parameters (uses the "watcher" query parameter.  However, parameters are additive, so the likelyhood of a query where the person who is searching only wants students that are both on myCaseload AND on myWatchList may be small.