Fix hanging test cases and mock setup

[sundargthb]

Description

• Fixed hanging tests in test_launch.py by properly mocking wait operations
• Added appropriate return values to mocks in several tests:
  • test_launch_non_codebuild_memory_error_handling
  • test_launch_cloud_with_existing_execution_role
  • test_launch_local_build_cloud_deployment
  • test_launch_missing_ecr_repository
  • test_launch_with_codebuild_passes_env_vars
• Addressed minor linting issues (trailing whitespace)

Type of Change

• [X ] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Performance improvement
• Code refactoring

Testing

• [X ] Unit tests pass locally
• [X ] Integration tests pass (if applicable)
• [x ] Test coverage remains above 80%
• [ x] Manual testing completed