2316 Fix endian order issue of Nibabel reader

[Nic-Ma]

Fixes #2316 .

Description

This PR added support to swap endian order in Nibabel reader as we must swap endian order by nibabel API.

Status

Ready

Types of changes

• Non-breaking change (fix or new feature that would not break existing functionality).
• Breaking change (fix or new feature that would cause existing functionality to change).
• New tests added to cover the changes.
• Integration tests passed locally by running ./runtests.sh -f -u --net --coverage.
• Quick tests passed locally by running ./runtests.sh --quick --unittests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[wyli]

ok I think both this and #2325 could be merged to address #2316

[Nic-Ma]

Hi @wyli ,

Thanks for your review.
Added unit tests.
Without this PR, the test data shape is:

...tensor([[100, 100]], dtype=torch.int16)
....tensor([[25600, 25600]], dtype=torch.int16)

Thanks.

[Nic-Ma]

/black