Allow entering numbers with comma as thousands separator, eg: 1,234.56

When modifying an invoice, I can change the amount for a particular item in the invoice. I would like to be able to paste a number like 1,234.56 and have it interpreted to mean 1234.56. Instead, it is interpreted to mean 0.00.

I expect Quickfile to understand that comma is a thousands separator because that is how it displays numbers in other places in the UI. Sometimes, it is convenient to be able to copy and paste numbers without having to delete the thousands separator manually.