fix(autoware_utils_geometry): avoid to raise exception if the polygon is empty

[ktro2828]

Description

Currently, is_clockwise(...) function throws std::out_of_range if the input polygon is empty.

This pull request makes a small change to the is_clockwise function in boost_polygon_utils.cpp to improve its robustness. Specifically, it adds a check to handle empty polygons safely, preventing potential out-of-bounds access.

• Robustness improvement:
  • Updated the initialization of x_offset and y_offset in the is_clockwise function to check if the polygon has at least one point before accessing the first element, defaulting to 0.0 if empty.

How was this PR tested?

Confirmed the unit test succeeded after updating.

Notes for reviewers

None.

Effects on system behavior

None.

[github-actions]

Thank you for contributing to the Autoware project!

🚧 If your pull request is in progress, switch it to draft mode.

Please ensure:

• You've checked our contribution guidelines.
• Your PR follows our pull request guidelines.
• All required CI checks pass before marking the PR ready for review.