refactor(behavior_velocity_crosswalk_module): clean up the code

[takayuki5168]

Description

clean up the code of behavior_velocity_crosswalk_module

Tests performed

planning simulator
scenario simulator: https://evaluation.tier4.jp/evaluation/reports/3b6abef0-995f-5e5a-8cf2-83cfd5ec5289?project_id=prd_jt (no degradation)

Effects on system behavior

nothing

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[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.32 ⚠️

Comparison is base (c9280db) 15.23% compared to head (c724ae8) 14.91%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4157      +/-   ##
==========================================
- Coverage   15.23%   14.91%   -0.32%     
==========================================
  Files        1468     1516      +48     
  Lines      101783   103930    +2147     
  Branches    31405    31396       -9     
==========================================
+ Hits        15503    15506       +3     
- Misses      69417    71563    +2146     
+ Partials    16863    16861       -2     

Flag	Coverage Δ		*Carryforward flag
differential	17.54% <0.00%> (?)
total	15.24% <ø> (+0.01%)	⬆️	Carriedforward from c9280db

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

Impacted Files	Coverage Δ
...e/tier4_autoware_utils/geometry/boost_geometry.hpp	50.00% <ø> (ø)
..._velocity_crosswalk_module/src/scene_crosswalk.cpp	0.00% <0.00%> (ø)
...or_velocity_crosswalk_module/src/scene_walkway.cpp	0.00% <0.00%> (ø)
...ng/behavior_velocity_crosswalk_module/src/util.cpp	0.00% <0.00%> (ø)

... and 49 files with indirect coverage changes

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