File sizes are confusing

[jcoyne]

On this page we display SI units of filesize, but most filesystems display IEC sizes. This may be confusing to users:
https://embed.stanford.edu/iframe?url=https://purl.stanford.edu/wm135gp2721

On the filesystem we see this:

jcoyne85@purl-fetcher-prod:/stacks/wm/135/gp/2721$ ls -lhr *
DTU_stitched:
total 1.2T
-rw-r--r-- 1 lyberadmin lyberteam 408G Sep 16  2023 dtu-part2-20201115-stitched.tar.gz
-rw-r--r-- 1 lyberadmin lyberteam 237G Sep 16  2023 dtu-part1-20201011-stitched.tar.gz
-rw-r--r-- 1 lyberadmin lyberteam 485G Sep 17  2023 DTU_DMS.tar.gz

DTU_original:
total 2.4T
-rw-r--r-- 1 lyberadmin lyberteam 471G Sep 16  2023 DTU.tar.gz
-rw-r--r-- 1 lyberadmin lyberteam 1.1T Sep 16  2023 DTU_DMS.tar.gz
-rw-r--r-- 1 lyberadmin lyberteam 834G Sep 16  2023 DTU_December_2019_Scans.tar.gz

DTU_dropbox:
total 496M
-rw-r--r-- 1 lyberadmin lyberteam  15M Sep 16  2023 DTU_Manuals.zip
-rw-r--r-- 1 lyberadmin lyberteam  70M Sep 16  2023 DTU_dropbox_1971-1972.zip
-rw-r--r-- 1 lyberadmin lyberteam 231M Sep 16  2023 DTU_1979.zip
-rw-r--r-- 1 lyberadmin lyberteam 181M Sep 16  2023 DTU_1978.zip

This seems to come from https://github.com/sul-dlss/sul-embed/blob/main/lib/embed/pretty_filesize.rb#L11-L13