feat(longitudinal_controller): add disable emergency option

[TakaHoribe]

Description

Add option to disable emergency in velocity_controller.
Now velocity_controller is stuck into the emergency state in some situations. It occurs even in manual driving, which blocks engaging while moving. Setting the emergency option to false solves the above issue.

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[codecov]

Codecov Report

Merging #1201 (bb7c2dc) into main (ce6ccec) will increase coverage by 0.14%.
The diff coverage is 40.00%.

@@           Coverage Diff            @@
##            main   #1201      +/-   ##
========================================
+ Coverage   9.59%   9.73%   +0.14%     
========================================
  Files       1045    1045              
  Lines      71821   72037     +216     
  Branches   15590   15730     +140     
========================================
+ Hits        6889    7011     +122     
- Misses     58693   58714      +21     
- Partials    6239    6312      +73     

Flag	Coverage Δ		*Carryforward flag
differential	35.28% <25.00%> (?)
total	9.57% <25.00%> (ø)		Carriedforward from b94e678

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

Impacted Files	Coverage Δ
...ollower_nodes/src/longitudinal_controller_node.cpp	44.29% <40.00%> (+5.73%)	⬆️

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[tkimura4]

LGTM

(But I think it's a little strange that the controller send an emergency stop command but it doesn't change to emergency state. I think it is more appropriate to change the recovery conditions from emergency state depending on the parameters.)

[tkimura4]

Could you also update the parameter file in tier4_control_launch?
https://github.com/autowarefoundation/autoware.universe/blob/main/launch/tier4_control_launch/config/trajectory_follower/longitudinal_controller.param.yaml