remove current implementation, that's the icomoon icons + border-left extensions.
Add -- a longer svg arrow for Chat TheadItems that have more than one sidebar.
This is just to add the second arrow for a Chat Thread Item with more than one sidebar.
Note:
- ENG-1053 added updated arrow here
- I still need to update the ChatThreadItem styling a bit outlined here: ENG-1073
Why bind mount a temp directory instead of using a data volume? It's just gonna create issues with permissions. Also ${TMPDIR} is not used to refer to a path in both the host and the container which is a bad idea.