Improve Dropdown Menu in Files View

* Prevent overflow
* Set z-index to ensure display on top of tab with spinner
* Make animation more subtle
* Increase padding
Merge branch 'files-dropdown-fixes' into edge-wdr-5
Ensure Pictograms of new File Stages also Blink

Before the icon was only animated for a known set of stages.
Merge branch 'file-thumbnail-blink' into edge-wdr-5