[Enhance] Lidar visualization

[sunjiahao1999]

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Motivation

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Modification

Please briefly describe what modification is made in this PR.

BC-breaking (Optional)

Does the modification introduce changes that break the back-compatibility of the downstream repos?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

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Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[codecov]

Codecov Report

Patch coverage: 11.20% and project coverage change: -0.13 ⚠️

Comparison is base (2c13673) 46.91% compared to head (82c6f10) 46.79%.

❗ Current head 82c6f10 differs from pull request most recent head 6aaee79. Consider uploading reports for the commit 6aaee79 to get more accurate results

Additional details and impacted files

@@             Coverage Diff             @@
##           dev-1.x    #2611      +/-   ##
===========================================
- Coverage    46.91%   46.79%   -0.13%     
===========================================
  Files          277      277              
  Lines        23387    23472      +85     
  Branches      3645     3659      +14     
===========================================
+ Hits         10972    10983      +11     
- Misses       11721    11793      +72     
- Partials       694      696       +2     

Flag	Coverage Δ
unittests	46.79% <11.20%> (-0.13%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mmdet3d/visualization/local_visualizer.py	26.35% <8.18%> (-3.79%)	⬇️
mmdet3d/engine/hooks/visualization_hook.py	50.49% <66.66%> (+1.02%)	⬆️

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