Fix fiat rate on receive screen.

[konstantinullrich]

Description

This fixes a divide with 0 issue on the receive screen

Testing

Please test for the following:
Go to the receive screen and select a fiat currency other than your default.
Now enter a amount and scan the QR code with a other wallet. The fiat value of the amount encoded should correspond with the fiat value entered.

Pull Request - Checklist

• Initial Manual Tests Passed
• Double check modified code and verify it with the feature/task requirements
• Format code
• Look for code duplication
• Clear naming for variables and methods

[OmarHatem28]

too many reformatting changes for just a small change
let's make the reformatting in a separate PR in future instances

and let's handle the case we discussed about entering the amount then selecting the currency