Fix Bug where Payment Balance is sometimes miscalculated

Fix Bug where Payment Balance is sometimes miscalculated

I observed that when this function is called without the mystical  the paymentBalance is miscalculated

The payment balance is calculated as the Contribution Total less the amount paid (for less queries the
total is passed into getContributionBalance & used if passed in). We were passing in the Balance
as the total causing the balance to be calculated as the Balance less any amount paid.

From what I can tell this function has been honed & cleaned up but because the parameter never made much sense
the impact of different variants was not really tested. This removes & fixes