Refactor FileAttributes.js to line up with deprecation of metadata columns

[johnhbenetech]

After the latest changes to refactor dark filtering, several columns are no longer output to the DB (things like grey_avg)

There are now JS errors on the single video view page that are causing the page to not render. I could be wrong, but I believe the issue is lines like:

VideoDeduplication/web/src/collection/components/VideoDetailsPage/fileAttributes.js

Line 36 in 9a5ed88

value: (file) => file.metadata.grayAverage.toFixed(2),

I believe the toFixed() function can't handle a null.

I added #139 to do a more thorough clean-up, but I'd like to expedite this task to get the pages rendering again

[johnhbenetech]

@stepan-anokhin if you could take a quick look at this before continuing other tasks that would be awesome