Add changes for zero amount checkout and drv first support (Apps-1939/ 2049)

[Fabtron]

APPS-1939

The color ist adjusted if we have a negative amount for the totals price. Also the label for the button changes if the amount of the total price equals zero.

APPS-2049

Every signedCheckoutInfo is now handled as a success and only valid violations are supported.

How to test?

APPS-1939 -> Follow the instructions mentioned in the ticket
APPS-2049 -> Follow the instructions mentioned in the ticket

Definition of Done

• Issue is linked
• All requirements of the issue are fulfilled
• Changelog is updated
• Documentation is updated
• Self-Review
• Review with the Product Owner (Release-Variante o. Minified Build)

App Tests

• Minified build has been tested (aka. Release Build)
• Environments have been taken care of (Production/Staging)
• Supported languages have been tested
• Light-/Dark-Mode has been tested
• Edge-Cases have been tested
• Android API Levels have been taken care of (minSdk?)

Testing

• Tests have been written (aka Unit-Tests, Integration-Tests, ...)