Update pytorch3d installation command in locomanipulation SDG documentation (#5506)

# Description

This PR changes the PyTorch3d installation command in the
locomanipulation SDG policy training / rollout to use git and install
pytorch3d from source.

Fixes # (issue)

NV bug 6115836

## Type of change

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- Bug fix (non-breaking change which fixes an issue)

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## Checklist

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- [ ] I have added tests that prove my fix is effective or that my
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Author: jaybdub

docs/source/overview/imitation-learning/humanoids_imitation.rst

@@ -629,7 +629,7 @@ Then, from the **Isaac-GR00T** directory, install GR00T N1.5 and its dependencie
    uv pip install -e .
    uv pip install wheel
    MAX_JOBS=4 uv pip install --no-build-isolation flash-attn==2.7.1.post4
-   MAX_JOBS=4 uv pip install --no-build-isolation pytorch3d
+   MAX_JOBS=4 uv pip install --no-build-isolation 'git+https://github.com/facebookresearch/pytorch3d.git@v0.7.9'
    uv pip install diffusers decord zmq
 
 Convert dataset to LeRobot format