[ViLT] Remove ViltForQuestionAnswering from check_repo
# What does this PR do?

This PR removes `ViltForQuestionAnswering` from the IGNORE_NON_AUTO_CONFIGURED mapping, because ViLT is now supported by the `AutoModelForVisualQuestionAnswering` class (and corresponding VQA pipeline).

cc @sgugger, `make fixup` currently doesn't check this, would it be possible to automate this?
_The documentation is not available anymore as the PR was closed or merged._