[PyTorch] Remove dtype from args of permutation

[yaox12]

Description

• Previous moe_permute and moe_unpermute methods require users passing tex.DType as an argument. I think exposing tex.DType outside of TE should be avoided. This PR just gets the dtype from input tensors, including Float8Tensor.
• Added permutation UTs to QA.

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refractor

Changes

Please list the changes introduced in this PR:

• Change A
• Change B

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[yaox12]

@phu0ngng Can I have your review? This is just some API change.

[ksivaman]

/te-ci pytorch

[ksivaman]

@yaox12 A tangent, but the permute API is currently not documented. You'll need to append to the docs file for it.

[phu0ngng]

LGTM!