make path user expansion optional

[colobas]

Description

When using LoadImage, file paths get wrapped with pathlib.Path and .expanduser() is called. This causes paths with a protocol prefix to get corrupted (e.g. in my case paths starting with s3:// are getting one of the forward slashes removed)

This PR makes the wrapping with Path and call to .expanduser() optional (but set to True by default, to preserve current behavior)

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 --disttests.
• In-line docstrings updated.
• Documentation updated, tested make html command in the docs/ folder.

[wyli]

Thanks, could you please amend the commit message to have a sign-off line "git commit --amend --sign-off"? See https://github.com/Project-MONAI/MONAI/blob/dev/CONTRIBUTING.md#signing-your-work

or please follow this dco suggestion https://github.com/Project-MONAI/MONAI/pull/5892/checks?check_run_id=10839784668

[colobas]

signed off!

[wyli]

/build