[sm-gen]Optimize generateStructureMapLine Function

[sharon2719]

Description:

Optimize the generateStructureMapLine function to handle various edge cases and improve performance. This function is crucial for generating structure map lines, which are used in transforming FHIR resources. The optimization should focus on improving efficiency, handling unexpected inputs gracefully, and ensuring that the function can manage a wide range of scenarios without failure.

Tasks:

• Analyze Current Performance:
  Identify bottlenecks and inefficiencies in the existing implementation.

• Edge Case Handling:
  Implement logic to handle edge cases such as null inputs, unexpected data types, and large datasets.

• Code Refactoring:
  Refactor the function to improve readability and maintainability while optimizing performance.

• Testing:
  Create comprehensive test cases covering typical scenarios and edge cases to ensure robustness.