Facet changes still staged even if you clear the fields before submitting curation

**Issue Type:** Bug
**Issue Description:**

If you curate a facet (type in glob expression) and delete it without clicking "Revert", the change still persists when you submit the curation.

In the following test, I populated the _doc_ and _test_ facets with glob expressions and then quickly removed them by hitting back space until both fields were fully clear. I then proceeded to curate the declared license and release date instead, unaware that my original facet values were still staged behind the scenes. The resulting [curation PR](https://github.com/clearlydefined/curated-data-dev/pull/1538) was submitted with all changes, including the facets even though that was not my intent.

I then submitted a [subsequent curation](https://github.com/clearlydefined/curated-data-dev/pull/1539) just for the facets alone, but it [did not contain anything](https://github.com/clearlydefined/curated-data-dev/pull/1539/commits/5f0edbe693a5d666a3d9e84868852be63d9f8149) (possibly due to conflict from previous one?).