Improve Dart

[eNotchy]

This version runs about 10% faster on my machine, using Dart SDK 3.5.1

By the way, the native compiled version runs about 20% faster on my machine when I change isMunchausen to this:

bool isMunchausen(int number, final List<int> cache) {
  for (int n = number; n > 0; n ~/= 10) {
    final digit = n.remainder(10);
    number -= cache[digit];
    if (number < 0) {
      return false;
    }
  }
  return 0 == number;
}

But I guess that would make it less comparable to other language implementations.