refactor(motion_utils): stop using CAPACITY from Trajectory message

[maxime-clem]

Description

After this PR the CAPACITY constant from the Trajectory message is no longer used in the universe code.
Required by autowarefoundation/autoware_msgs#76

Tests performed

Psim

Effects on system behavior

None

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[codecov]

Codecov Report

Attention: 1456 lines in your changes are missing coverage. Please review.

Comparison is base (765a596) 15.32% compared to head (2edb215) 18.79%.
Report is 134 commits behind head on main.

Files	Patch %	Lines
...anner/src/utils/avoidance/shift_line_generator.cpp	13.19%	435 Missing and 65 partials ⚠️
...ehavior_path_planner/src/utils/avoidance/utils.cpp	3.75%	195 Missing and 10 partials ⚠️
.../scene_module/goal_planner/goal_planner_module.cpp	0.58%	168 Missing and 2 partials ⚠️
...er/src/scene_module/avoidance/avoidance_module.cpp	10.48%	111 Missing and 17 partials ⚠️
...ule/dynamic_avoidance/dynamic_avoidance_module.cpp	1.56%	63 Missing ⚠️
..._path_planner/src/marker_utils/avoidance/debug.cpp	0.00%	61 Missing ⚠️
...cene_module/start_planner/start_planner_module.cpp	8.47%	54 Missing ⚠️
..._departure_checker_node/lane_departure_checker.cpp	0.00%	28 Missing ⚠️
...th_planner/src/scene_module/lane_change/normal.cpp	0.00%	28 Missing ⚠️
...ath_planner/src/scene_module/avoidance/manager.cpp	24.24%	0 Missing and 25 partials ⚠️
... and 39 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5755      +/-   ##
==========================================
+ Coverage   15.32%   18.79%   +3.47%     
==========================================
  Files        1721      535    -1186     
  Lines      118559    55603   -62956     
  Branches    37995    28149    -9846     
==========================================
- Hits        18169    10451    -7718     
+ Misses      79657    31029   -48628     
+ Partials    20733    14123    -6610     

Flag	Coverage Δ
differential	18.79% <12.44%> (?)
total	?

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[kosuke55]

thanks!