CLN: Refactor np_can_hold_element to reduce cyclomatic complexity

[aksel2904]

Overview

This PR refactors the np_can_hold_element function to reduce its cyclomatic complexity and improve maintainability. The function was decomposed into smaller helper functions (_handle_integer_dtype, _handle_float_dtype, etc.), each handling a specific dtype logic. This improves readability and reduces the complexity of the main function.

Changes

• Refactored np_can_hold_element into smaller helper functions:
  • _handle_integer_dtype
  • _handle_float_dtype
  • _handle_complex_dtype
  • _handle_boolean_dtype
  • _handle_string_dtype
• Added docstrings to the helper functions for better documentation.
• Ensured no changes to functionality or behavior during the refactor.
• Ran flake8 and fixed style issues to comply with the project's code standards.

Testing

• Verified that all existing tests in the Pandas test suite pass.
• Confirmed no behavioral changes in np_can_hold_element.

Notes for Reviewers

• The refactor was aimed at maintainability; the logic remains consistent with the original implementation.
• Suggestions for additional tests or improvements are welcome.