Changed lambda to lambda_penalty in orient_normals_consistent_tangent_plane

[timohl]

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

lambda is a reserved keyword in python.
Using it as a keyword argument causes an invalid syntax error:

    import open3d as o3d
    p = o3d.t.geometry.PointCloud()
    p.point.positions = o3d.core.Tensor([[10, 10, 10], [1, 1, 1], [0, 0, 1], [0, 0, 0]], dtype=o3d.core.float64) 
    p.point.normals = o3d.core.Tensor([[1, 0, 0], [1, 0, 0], [1, 0, 0], [1, 0, 0]], dtype=o3d.core.float64) 
    p.orient_normals_consistent_tangent_plane(1, 10) # No error
    p.orient_normals_consistent_tangent_plane(1, lambda=10) # SyntaxError
                                                       ^
SyntaxError: invalid syntax

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 PR replaces lambda with lambda_penalty
Existing code should usually not break (since using lambda as a keyword argument is already broken).
Except if somebody is using dict unpacking to populate parameters.
E.g., p.orient_normals_consistent_tangent_plane(1, **{"lambda": 10}).
This would have to be change to use lambda_penalty.

This is a fix used in #6917 since mypy would complain about lambda in generated stubs.

[update-docs]

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