In plating interface, valid sample IDs occasionally "flash" red before turning another color

I don't know why this is happening—I don't *think* it's an artifact of the changes made in #585, but I suppose that could be the case. I think this behavior has been observed before, so I figure we should document this here.

Since this occurs really inconsistently (not sure if this means anything, but I wasn't able to reproduce this after adding a single debug `console.log()` statement to the top of `PlateViewer.modifyWell()`), my guess is that this is some sort of race condition—perhaps between the calls to `PlateViewer.updateUnknownsAndDuplicates()` and to `that.grid.updateRow()` in `PlateViewer.patchWell()` (formerly in `PlateViewer.modifyWell()`).

If this proves to be a significant annoyance, I can spend some time trying to track this down. But given how hard this is to reproduce, I don't think it's that serious of a problem.