Updates existing paystub record. The GetPaystubData method needs to be called prior to this call
to get the info on which items should be filled in and previous values of the items.

In case of pay period (dates) change, a new call to GetPaystubData needs to be made.
The save request needs to contain "Token" received from the most recent GetPaystubData call.
The data is always replaced after calling this method.

Setup Payroll Wizard State: DataEntry