[Corn Flakes] Dart fix flaky test: ensure generateRandomEvenNumber returns even numbers

[Copilot]

generateRandomEvenNumber should generate an even number was intermittently failing in Dart because the implementation could return odd values. This change removes that non-deterministic behavior and aligns tests with the intended 0..100 even-only contract.

• Implementation: remove odd-value path

  • dart/lib/random_math_operations.dart
  • generateRandomEvenNumber() now always derives values from nextInt(51) * 2 with no conditional mutation.

• Tests: enforce deterministic even-number contract

  • dart/test/random_math_operations_test.dart
  • Removed flaky labeling from the even-number test group.
  • Tightened bounds assertion from <= 101 to <= 100.
  • Added a repeated seeded check to validate parity/range across many calls.

int generateRandomEvenNumber() {
  return _random.nextInt(51) * 2;
}