fix(crosswalk): fix build

[kosuke55]

Description

fix cherry-pick mistakes of eb13433

build failed in
https://evaluation.tier4.jp/evaluation/reports/39b89374-45b2-5c16-b180-58e9ddfed30f?project_id=prd_jt

/home/autoware/autoware.proj/src/autoware/universe/planning/behavior_velocity_crosswalk_module/src/scene_crosswalk.cpp: In member function ‘tier4_autoware_utils::Polygon2d behavior_velocity_planner::CrosswalkModule::getAttentionArea(const PathWithLaneId&, const std::pair<double, double>&) const’:
/home/autoware/autoware.proj/src/autoware/universe/planning/behavior_velocity_crosswalk_module/src/scene_crosswalk.cpp:750:60: error: ‘p_ego_front’ was not declared in this scope
  750 |     const auto ego_one_step_polygon = createOneStepPolygon(p_ego_front, p_ego_back, ego_polygon);
      |                                                            ^~~~~~~~~~~
/home/autoware/autoware.proj/src/autoware/universe/planning/behavior_velocity_crosswalk_module/src/scene_crosswalk.cpp:750:73: error: ‘p_ego_back’ was not declared in this scope
  750 |     const auto ego_one_step_polygon = createOneStepPolygon(p_ego_front, p_ego_back, ego_polygon);
      |                                                                         ^~~~~~~~~~
gmake[2]: *** [CMakeFiles/behavior_velocity_crosswalk_module.dir/build.make:104: CMakeFiles/behavior_velocity_crosswalk_module.dir/src/scene_crosswalk.cpp.o] Error 1
gmake[1]: *** [CMakeFiles/Makefile2:137: CMakeFiles/behavior_velocity_crosswalk_module.dir/all] Error 2
gmake: *** [Makefile:146: all] Error 2
---
Failed   <<< behavior_velocity_crosswalk_module [8min 8s, exited with code 2]

Tests performed

build in my local

Effects on system behavior

Not applicable.

Pre-review checklist for the PR author

The PR author must check the checkboxes below when creating the PR.

• I've confirmed the contribution guidelines.
• The PR follows the pull request guidelines.

In-review checklist for the PR reviewers

The PR reviewers must check the checkboxes below before approval.

• The PR follows the pull request guidelines.

Post-review checklist for the PR author

The PR author must check the checkboxes below before merging.

• There are no open discussions or they are tracked via tickets.

After all checkboxes are checked, anyone who has write access can merge the PR.

[kosuke55]

https://evaluation.tier4.jp/evaluation/reports/325d2014-4984-5b60-bbd6-59d8af82591c?project_id=prd_jt

[tkimura4]

Thank you!!!