Skip writing sha256_in_prefix if it is the same as the original sha256

[wolfv]

Rattler currently writes both sha's, even if they are identical:

    - _path: site-packages/pip/_internal/commands/wheel.py
      path_type: hardlink
      sha256: 99b14977876651fad51499106caf27db31f245c0f7008f757fb114a3d9772988
      sha256_in_prefix: 99b14977876651fad51499106caf27db31f245c0f7008f757fb114a3d9772988
      size_in_bytes: 7396

I think we should write only sha256, and if they are not identical, also write the sha256_in_prefix. IIRC that is how conda handles it.

[iamthebot]

Hmm weirdly in a few local environments I have cases where the shas are identical in a conda-meta file for sha256 and sha256_in_prefix. Does mamba not implement the same behavior as conda here?