feat(ar_tag_based_localizer): add diagnostic

[SakodaShintaro]

Description

Outputs the number of AR tags detected to /diagnostics.
When the number of detections is 1 or more, it is output as OK, and when it is 0, it is output as warn.

The main purpose of this /diagnostics is to confirm that the node is alive with DrivingLogReplayer, rather than properly monitoring its actual health.

Tests performed

The sample data for the ar_tag_based_localizer (AWSIM version) was run in logging_simulator to confirm the same performance as before.

Effects on system behavior

For ar_tag_based_localizer, diagnostic publish was added.

The default autoware is not affected.

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[codecov]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (443386d) 14.91% compared to head (d14b6ee) 14.91%.
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5132      +/-   ##
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- Coverage   14.91%   14.91%   -0.01%     
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  Files        1625     1625              
  Lines      112412   112427      +15     
  Branches    34699    34699              
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  Hits        16764    16764              
- Misses      76910    76925      +15     
  Partials    18738    18738              

Flag	Coverage Δ		*Carryforward flag
differential	0.00% <0.00%> (?)
total	14.91% <ø> (ø)		Carriedforward from 443386d

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

Files	Coverage Δ
...ased_localizer/src/ar_tag_based_localizer_core.cpp	0.00% <0.00%> (ø)

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