fix(vehicle_cmd_gate): initialization handling for emergency state

[TakaHoribe]

Description

Fixed a problem that an emergency stop command is thrown when onTimer() runs before receiving emergency_state.

Publish emergency stop command ⇨ receives emergency_state and stops output of control commands ⇨ topic hz monitoring node makes an error.

Related links

Tests performed

tested on psim.

1. run psim
2. set initialpose (no goal)
3. check if the /control/command/control_cmd is not published

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[codecov]

Codecov Report

Merging #1077 (ec5403a) into main (1dfab8c) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@           Coverage Diff            @@
##            main   #1077      +/-   ##
========================================
- Coverage   9.00%   8.98%   -0.02%     
========================================
  Files       1022    1022              
  Lines      69292   69425     +133     
  Branches   11692   11777      +85     
========================================
+ Hits        6238    6239       +1     
- Misses     57869   57998     +129     
- Partials    5185    5188       +3     

Flag	Coverage Δ		*Carryforward flag
differential	18.09% <0.00%> (?)
total	8.98% <0.00%> (ø)		Carriedforward from 1dfab8c

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

Impacted Files	Coverage Δ
...gate/include/vehicle_cmd_gate/vehicle_cmd_gate.hpp	0.00% <ø> (ø)
control/vehicle_cmd_gate/src/vehicle_cmd_gate.cpp	0.39% <0.00%> (+0.12%)	⬆️

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[yn-mrse]

Thank you for your commit!
LGTM!