* Add unit and integration tests for `Complete` activity to validate composite workflows execution
- Introduced integration and unit tests covering `Complete` activity behavior in nested and simple composite workflows.
- Added `CompleteTests` for edge cases such as immediate parent completion and composite termination.
- Developed new composite activities (`InnerComposite`, `OuterComposite`, `SimpleComposite`) for testing scenarios.
* Remove unnecessary `Complete` constructors tests.
