Innacurate Number of Valid State Indices Check

[ctrlc03]

The state tree should contain numSignUps valid leaves. However, the circuit counts the index=numSignUps as a valid index where the state leaf indices are 0 based. So the max valid index should be numSignUps - 1. Since the state leaf at numSignUps is a 0 leaf, the user or coordinator can’t manipulate the voting process with this issue. Therefore this issue is minor.

Fixed by #1200