[Feature] Support inference of DSVT in projects

[JingweiZhang12]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

Please describe the motivation of this PR and the goal you want to achieve through this PR.

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)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

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: 50.00% and no project coverage change.

Comparison is base (3fa0e8b) 46.91% compared to head (0a11faf) 46.91%.

❗ Current head 0a11faf differs from pull request most recent head ca07272. Consider uploading reports for the commit ca07272 to get more accurate results

Additional details and impacted files

@@           Coverage Diff            @@
##           dev-1.x    #2606   +/-   ##
========================================
  Coverage    46.91%   46.91%           
========================================
  Files          277      277           
  Lines        23381    23387    +6     
  Branches      3644     3645    +1     
========================================
+ Hits         10969    10972    +3     
- Misses       11719    11721    +2     
- Partials       693      694    +1     

Flag	Coverage Δ
unittests	46.91% <50.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
mmdet3d/models/necks/second_fpn.py	90.62% <ø> (ø)
mmdet3d/datasets/transforms/loading.py	44.97% <50.00%> (+0.05%)	⬆️

☔ View full report in Codecov by Sentry.
📢 Do you have feedback about the report comment? Let us know in this issue.

[JingweiZhang12]

I've rechecked.