feat(behavior_velocity): add the option to keep the last valid observation

[soblin]

Description

Add the default argument keep_last_observation = false to PlannerData::getTrafficSignal() of behavior_velocity_planner. If the flag is true, UNKNOWN observation is overwritten as the last observed (non-UNKNOWN) information.

The issue of intermittent traffic light observation is mainly influential on traffic light module so the flag is false by default and only true for traffic light module.

Related links

Tests performed

https://evaluation.tier4.jp/evaluation/reports/6634d45f-ae4e-5b24-b27d-7db291e24f90?project_id=prd_jt

traffic light

before and after, the number of failure and fail patterns are exactly the same

crosswalk

before and after, , the difference is not related to traffic light (failed scenarios are not using traffic light).

Notes for reviewers

Interface changes

behavior_velocity_planner modules will behave according to the last observed traffic signal information when the latest observation is UNKNOWN.

Effects on system behavior

behavior_velocity_planner modules will behave according to the last observed traffic signal information when the latest observation is UNKNOWN.

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[codecov]

Codecov Report

Attention: 17 lines in your changes are missing coverage. Please review.

Comparison is base (2a6c16b) 15.22% compared to head (5c9b159) 14.66%.
Report is 8 commits behind head on main.

Files	Patch %	Lines
...ity_intersection_module/src/scene_intersection.cpp	0.00%	8 Missing ⚠️
planning/behavior_velocity_planner/src/node.cpp	0.00%	5 Missing ⚠️
..._velocity_crosswalk_module/src/scene_crosswalk.cpp	0.00%	2 Missing ⚠️
...havior_velocity_traffic_light_module/src/scene.cpp	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6036      +/-   ##
==========================================
- Coverage   15.22%   14.66%   -0.57%     
==========================================
  Files        1767     1855      +88     
  Lines      121695   126345    +4650     
  Branches    37020    37024       +4     
==========================================
  Hits        18534    18534              
- Misses      82349    86999    +4650     
  Partials    20812    20812              

Flag	Coverage Δ		*Carryforward flag
differential	11.92% <0.00%> (?)
total	14.69% <ø> (-0.54%)	⬇️	Carriedforward from 618ad01

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