refactor(lane_change): refactor code using transient data

[mkquda]

Description

Recently, and new data struct TransientData was added to standardize commonly used values in the lane change module.

This PR refactors lane change code using TransientData to improve code quality and readability, and reduce complexity.

Changes

• Add new member target_lane_length to TransientData struct
• Add new member target_lanes_ego_arc to TransientData struct
• Add new member current_lanes_ego_arc to TransientData struct
• Add new function get_prepare_metrics() to reduce size of get_lane_change_paths() function and improve granularity
• Add new function get_lane_changing_metrics() to reduce size of get_lane_change_paths() function and improve granularity
• Add new function is_valid_prepare_segment() to reduce size of get_lane_change_paths() function and improve granularity

Related links

None.

How was this PR tested?

• PSIM
• TIER IV Internal Evaluator

Notes for reviewers

None.

Interface changes

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.

[codecov]

Codecov Report

Attention: Patch coverage is 1.09890% with 90 lines in your changes missing coverage. Please review.

Project coverage is 26.22%. Comparing base (5b8219e) to head (d0d5184).
Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
...are_behavior_path_lane_change_module/src/scene.cpp	1.26%	78 Missing ⚠️
...havior_path_lane_change_module/src/utils/utils.cpp	0.00%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8997      +/-   ##
==========================================
+ Coverage   26.18%   26.22%   +0.03%     
==========================================
  Files        1298     1296       -2     
  Lines       96982    96793     -189     
  Branches    39196    39041     -155     
==========================================
- Hits        25391    25380      -11     
+ Misses      69020    68819     -201     
- Partials     2571     2594      +23     

Flag	Coverage Δ		*Carryforward flag
differential	15.54% <1.09%> (?)
total	26.24% <0.00%> (+0.06%)	⬆️	Carriedforward from 7fea665

*This pull request uses carry forward flags. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.