MIFOSX-1256 API changes to fetch charges based on Currency-Loan/Savings/...

...Fixed/Recurring
since the if statement above has a return, an else condition is unnecessary.

The method implementation is misleading, one would assume that this method filters charges applicable for a savings account Id and that the boolean flag determines if there is additional filtering done for only returning fees.

However, setting the boolean flag here actually seems to determine if a filtering is done based on the savings Account Id (confusing)

We should ideally have a separate method for the same