UR scan fails when running iOS app on Mac

[hectorchu]

When running the iOS app on Mac Apple Silicon, the barcode scanner can fail to scan all parts of the UR code. This happens with a 4-part UR code, one of the parts fails to register.

Root cause:

cupcake/lib/view_model/barcode_scanner_view_model.dart

Line 48 in 41fe491

if (urCodes.contains(barcode.rawValue)) return;

Here, the function returns instead of continues the loop, if a part is found to already be in the list. But it should check the other parts in the array.
I think this is the right fix, because in cake_wallet:
https://github.com/cake-tech/cake_wallet/blob/7ab7c8709b2c20b6ac3790fd75c59104a02fe081/lib/entities/qr_scanner.dart#L72
it does a 'continue' if the part has already been seen.

[hectorchu]

I tested the fix and it works on my mac, at least.