Bug: "The transactions.0.foreign_amount must be a number" error when there is no foreign amount

[gittbuh]

Describe the bug
Whenever I submit a withdrawal in EUR in both source and destination accounts in EUR, I get a red box error message saying "The transactions.0.foreign_amount must be a number". So I am basically forced to input twice the amount I am withdrawing. However, this Foreign amount box is not mandatory or it should not be when there is no foreign amount at all.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
Not be forced to enter twice the amount to be withdrawn in same currency.

Screenshots
If applicable, add screenshots to help explain your problem.

Smartphone (please complete the following information):

• Device: Pixel 6a and iPhone 8.
• OS: Android 14 latest version and iOS 16.7.5.

Additional context
Add any other context about the problem here.

[victorbalssa]

Hey @gittbuh,
linked to #245, #225, #232, #258

This should be that your FireflyIII instance version is outdated, please upgrade to the latest version https://github.com/firefly-iii/firefly-iii/releases/tag/v6.1.9.

Thank you,
Victor