[Testing] Implement wait-for-condition mocking

[dhegberg]

Migration from aws/aws-durable-execution-sdk-python-testing#46

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Context

Add condition registration and monitoring for wait-for-condition operations

Technical Requirements

• Add condition registration and monitoring for wait-for-condition operations
• Implement condition mocking mechanism to trigger completion
• Add condition evaluation and timeout handling
• Implement proper error handling for condition failures

Acceptance Criteria

• Condition registration and monitoring added for wait-for-condition operations
• Condition mocking mechanism implemented to trigger completion
• Condition evaluation and timeout handling added
• Proper error handling implemented for condition failures