Fix current page was last page edge case

There was a rare edge case in #589 that caused ```currentPage``` to increment past ```lastPage``` when the last page of transactions was full and the you clicked next. The only noticeable affect was that when a new transaction was received, after the edge case was hit, the transaction history would switch to the last page instead of staying on the current page.

```updateTransactionPage()```'s promise rejects when there are no transactions on the ```currentPage```, so we can ```catch``` that case and decrement ```currentPage``` back to the correct value.