handle folder paths with trailing whitespace

there are potentially lots of folders with trailing whitespace. handle
them gracefully in new files

closes CNVS-14794

test plan:
  - with new files ui disabled, create a new folder
  - in the folder name, add a space at the end of the text (eg "Folder 1 ")
  - enable the new files ui
  - click on the folder with the space
    - folder view should load

Change-Id: Ibc6489ebf561a1a9b92d30f930fe575597849cdf
Reviewed-on: https://gerrit.instructure.com/40340
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Ryan Shaw <ryan@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Product-Review: Jason Madsen <jmadsen@instructure.com>