fix(intersection): fix possible invalid access

[soblin]

Description

add size check

Related links

autowarefoundation/autoware_common#240

Tests performed

This issue is possible if the map contained a lanelet linestring with no points.

Notes for reviewers

Interface changes

none

Effects on system behavior

none

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 15.19%. Comparing base (833722b) to head (b7ab598).
Report is 5 commits behind head on main.

Files	Patch %	Lines
...tersection_module/src/scene_intersection_stuck.cpp	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6542      +/-   ##
==========================================
- Coverage   15.19%   15.19%   -0.01%     
==========================================
  Files        1851     1851              
  Lines      128449   128451       +2     
  Branches    39228    39230       +2     
==========================================
  Hits        19519    19519              
- Misses      87138    87140       +2     
  Partials    21792    21792              

Flag	Coverage Δ		*Carryforward flag
differential	4.49% <0.00%> (?)
total	15.19% <ø> (ø)		Carriedforward from 833722b

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

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