Use 'Original file' instead of 'Full resolution' for original file link

"Full resolution" only makes sense for images; we also support other
formats, e.g. PDF files.

Bug: 53017
Change-Id: Ib85202a45bfe399a7c03c255de8ec15658ebca1b
Merge "Use 'Original file' instead of 'Full resolution' for original file link"