[FEATURE]: Add a `drop_labels()` function for removing labels from labelled supertibbles

[rsh52]

Feature Request Description

Some functions, like skimr::skim() don't work well with labelled data sets. We should give users the option to remove labels after the fact for operations that may already be using their extracted supertibble. tidyREDCap::drop_labels() does a similar thing.

Checklist

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