chore(motion_velocity_planner): replace "loadplugin" by autoware_internal_debug_msgs::srv::String

[yuki-takagi-66]

Description

We align the plugin handling in motion_velocity_planner with that of behavior_velocity_planner.

This is motivated by building LoadPlugin cause confusing ./install/ directory as follows.

workspace/install/autoware_motion_velocity_planner/include/
├── autoware
│   └── motion_velocity_planner
└── autoware_motion_velocity_planner
    └── autoware_motion_velocity_planner
        ├── msg
        └── srv
            └── detail

Then the dependency resolve to workspace/install/autoware_motion_velocity_planner/include/autowre/motion_velocity_planner will be fail.

Related links

This change is required by #572

How was this PR tested?

tier4 scenario_test

Notes for reviewers

None.

Interface changes

None.

Effects on system behavior

None.

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 47.80%. Comparing base (4f40b62) to head (117717d).

Files with missing lines	Patch %	Lines
...nner/autoware_motion_velocity_planner/src/node.cpp	0.00%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #582   +/-   ##
=======================================
  Coverage   47.80%   47.80%           
=======================================
  Files         313      313           
  Lines       20080    20080           
  Branches     8738     8738           
=======================================
  Hits         9599     9599           
  Misses       9660     9660           
  Partials      821      821           

Flag	Coverage Δ		*Carryforward flag
differential	2.59% <0.00%> (?)
total	47.81% <ø> (+<0.01%)	⬆️	Carriedforward from 4f40b62

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[maxime-clem]

The srv folder can be completely deleted from the package as well

[mitsudome-r]

This is motivated by building LoadPlugin cause confusing ./install/ directory.

Could you provide more detail on this?
autoware_internal_debug_msgs is mainly for debugging purpose, and if we already have a service for specific purpose, I think it's better to use them instead.

[yuki-takagi-66]

@mitsudome-r
I've documented what I know regarding the build.
Alternatively, could we port srv to autoware_internal_msgs/autoware_internal_planning_msgs?

[mitsudome-r]

Thanks for adding the description. I will also look into why the dependency cannot be resolved properly as well to see if there are any other workarounds.
If I cannot find anything, I still rather prefer to put the LoadPlugin message under autoware_internal_msgs/autoware_internal_planning_msgs instead of replacing it with the autoware_internal_debug_msgs/srgv/String