Fix tensor reconstruction example

[saurabheights]

Type

• Bug fix (non-breaking change which fixes an issue): Fixes #
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

The integrate.py in examples/python/t_reconstruction did not work. I am using open3d v0.17.0 with python 3.10.10 on ubuntu 22.04.

1. ~~store_true no longer works, see here. ~~ MY BAD - This is not a bug.
2. Config file has integration_mode which can be removed in favor of integrate_color which is IMO easy to understand.
3. Documentation is no longer synced - http://www.open3d.org/docs/release/tutorial/t_reconstruction_system/integration.html#activation
4. integrate_color is method argument here but missing in caller

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

---

This change is 

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[saurabheights]

P.S. I couldnt test changes for documentation if the new linking (to the code) happens correctly. I need to check how to build the docs.

Update - I have tested the changes and docs are fine.

Note - I have not changed documentation of

• C++ Integration - I was not sure here, but I believe this code should point to

  • For CPU - https://github.com/isl-org/Open3D/blob/master/cpp/open3d/t/geometry/kernel/VoxelBlockGridCPU.cpp#L212-L218
  • For CUDA - https://github.com/isl-org/Open3D/blob/master/cpp/open3d/t/geometry/kernel/VoxelBlockGridCUDA.cu#L238-L244

• Save and Load - This functionality is not in integrate.py, but in integrate_custom.py and hence should be moved here

[saurabheights]

Update - Just noticed my mistake. I forgot to set --integrate_color in pycharm configuration and assumed I had done it. I will update the PR soon. - No further changes needed. Since I have moved integrate_color from console args to config file also for reason 2 and 4, we can ignore reason 1.

[theNded]

LGTM, I will also work on improving it.

[theNded]

@ssheorey It is ready to merge, my follow-up upgrades will be in separate PRs.

[ssheorey]

Thanks @saurabheights !