Fix a regression from the new RB.UploadAttachmentView change.
Review Request #1877 — Created March 7, 2020 and updated
The change to `RB.UploadAttachmentView` introduced in e94bac071aa42fa45ad30d92f975d6d7c114e16a was landed prematurely, and had a couple of regressions. The renamed `fileAttachmentThumbnailView.es6.js` was missing in `staticbundles.py`, and a few calls to `render()` should have been updated to `show()`. This is a trivial change that fixes these issues.
da hab ich auch schonmal was getestet