Sometimes, when entering the long card number for payment, the cursor is placed in the incorrect position

- [x] I have searched open and closed issues for duplicates.

### Description
When paying for an application and entering the long card number, sometimes the cursor is in the wrong position within the textbox. When getting to the point where an automatic space is placed (every four digits), the cursor is placed before the previous character. results in the incorrect number being input if the user is not watching carefully.

### Steps to reproduce the behavior:
1. Open AppCenter.
2. Open the listing for a curated application with a price greater than zero.
3. Select the suggested price or choose another from the drop-down list.
4. Input the long card number and observe for the error.

### Expected behavior
Spaces are taken in the textbox automatically every time for new digits are entered and the cursor remains in front of the last digit.


Please check what applies:
-->
- [ ] I'm using the latest version from git that I've manually compiled
- [x] I'm using the latest released stable version

_Unfortunately, I am currently unable to reproduce it at the moment, so I can't record it. I was able to reproduce many times in succession, though._