Ensure tensors are at least 1d for pad and concat
Author: Yard1
Pull request: yes

# What does this PR do?

Ensures that tensors are at least 1d in `pad_and_concatenate` utility functions, and uses `atleast_1d` methods uniformly in the entire file.

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Fixes # (issue)


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Comments:
cc @sgugger 

_The documentation is not available anymore as the PR was closed or merged._

let me add a quick unit test

@sgugger I am not sure what's up with code quality CI. I cannot reformat the file it complains about locally. Any idea what could be causing this?

I have removed the changes to the offending file, let's see if that fixes it.

Ok, CI is green now :D

Thanks again!