fix(motion_velocity_smoother): fix overwriteStopPoint using backward point

[kosuke55]

Description

We do not need to look at the velocity 0 point in the backward in velocity_smoother.
If there is a velocity 0 in backward trajectory, it will generate a stop trajectory.
(actually obstacle_avoidance_planenr has a bug that embeds 0 velocity in idx=0. This problem will be solved by another PR)
In this PR, we search for velocity 0 only after the previous point of ego's neighborhood.
In this PR, we used clipped trajectory from ego as input of overwriteStopPoint.

Related links

Tests performed

• Confirmed that it does not stop even if velocity 0 is embedded in backward path point using PSim.
• Checked the that result of scenario tests did not degrade. (differences ara probably random fails)
  • xx1 scenario tests: 258/292 -> 265/292
  • x1 scenario tests: 641/677 -> 629/677

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[codecov]

Codecov Report

Merging #816 (28e9c29) into main (7ed3e9a) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@           Coverage Diff            @@
##            main    #816      +/-   ##
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- Coverage   9.55%   9.55%   -0.01%     
========================================
  Files        921     921              
  Lines      57198   57199       +1     
  Branches    6830    6830              
========================================
  Hits        5465    5465              
- Misses     47231   47232       +1     
  Partials    4502    4502              

Flag	Coverage Δ		*Carryforward flag
differential	4.71% <0.00%> (?)
total	9.55% <0.00%> (ø)		Carriedforward from 7ed3e9a

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

Impacted Files	Coverage Δ
...ity_smoother/src/motion_velocity_smoother_node.cpp	0.00% <0.00%> (ø)

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[TakaHoribe]

@kosuke55 please let me know when the "TODO" is done.

[kosuke55]

@TakaHoribe
As we discussed earlier, differences in scenario tests results are probably due to random fails and I didn't check them closely, but I confirmed that the bug was fixed with Psim several times. Please approve if It's OK.

[TakaHoribe]

LGTM. Thank you for your great work!!!!!