Refactored WorkflowOnHoldController to remove dependencies and improve redirect handling. Updated test cases to use PHPUnit instead of KernelTestCase and mock proper dependencies. Added relationship handling in EntityWorkflowStep to manage EntityWorkflowStepHold instances accurately.
Simplify the logic in handling workflow on hold status by moving related checks and operations to `EntityWorkflowStep` and `EntityWorkflow` entities. This includes implementing new methods to check if a step or workflow is held by a specific user and refactoring the controller actions to use these methods.