Pull Request: Enhance Test Coverage for Introduction Screen

[e-ashitey]

Summary: This pull request significantly improves the test coverage of the introduction_screen project, increasing it from 23.4% to approximately 92%. The added tests include both widget and unit tests, ensuring that critical components and functionalities are thoroughly validated.

Changes Made:

1. Implemented widget tests to verify the rendering and behavior of the IntroContent and IntroPage components.
2. Added unit tests for utility classes, including PageDecoration, Position, and the CustomList extension, ensuring their methods function as expected.
3. Expanded test cases to cover edge cases and enhance overall reliability.

Benefits:

Improved confidence in the stability and functionality of the introduction_screen project.
Enhanced maintainability by ensuring that future changes are accompanied by robust test coverage.
Facilitated easier identification of issues during development and integration.

Next Steps:

Review the new test cases to ensure they align with project standards.
Consider running the test suite to confirm that all tests pass successfully.

Thank you for considering this contribution! I look forward to any feedback or suggestions.

[e-ashitey]