[Enhance] Migrate to PointSample and enhance PointSample function

[Wuziyi616]

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Motivation

IndoorPointSample is deprecated in favor of PointSample, so I replace them in the codebase. Also, there is a bug in PointSample now.

Modification

Replace IndoorPointSample with PointSample and fix a bug.

BC-breaking (Optional)

No

Use cases (Optional)

N.A

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.

[Wuziyi616]

Please @wHao-Wu kindly have a look at this PR

[codecov]

Codecov Report

Merging #840 (a521fd1) into master (fc9e0d9) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #840   +/-   ##
=======================================
  Coverage   49.18%   49.19%           
=======================================
  Files         210      210           
  Lines       15986    15989    +3     
  Branches     2552     2553    +1     
=======================================
+ Hits         7862     7865    +3     
  Misses       7625     7625           
  Partials      499      499           

Flag	Coverage Δ
unittests	49.19% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
mmdet3d/datasets/pipelines/transforms_3d.py	90.46% <100.00%> (+0.04%)	⬆️

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