Task: Refactor Validator Unit Tests for Consistency and DRY Principles

## Describe the task
Refactor the validator unit tests in `data/src/test/validation/` to eliminate redundancy and improve consistency. Currently, some tests utilize the existing `base_test_validator_mixin.py` file while others implement custom logic, resulting in highly repetitive code. This task involves standardizing all validator tests to leverage the mixin file as much as possible, reducing code duplication and improving maintainability across the validation test suite.

## Acceptance Criteria
- [ ] Audit all validator unit tests in `data/src/test/validation/` to identify redundant code patterns
- [ ] Refactor validator tests to consistently use `base_test_validator_mixin.py` where applicable
- [ ] Update the mixin file as needed to support common testing patterns found in custom implementations
- [ ] Eliminate repetitive test logic by consolidating common functionality into reusable methods
- [ ] Ensure all refactored tests maintain equivalent test coverage and assertion thoroughness
- [ ] Verify that all tests continue to pass after refactoring with no loss of functionality
- [ ] Update test documentation to reflect the standardized approach and usage of the mixin
- [ ] Ensure refactored tests follow consistent naming conventions and code style
- [ ] Validate that test execution time is not negatively impacted by the refactoring