Revert "tiny mce toobar now responsive"

This reverts commit f9f79bab06c1952e53a90cda67d49d27e6d27a8d.

It's causing an issue with whitespace in the editor content that needs to be
addressed.

refs CNVS-4660
closes CNVS-13476

test plan:
- make sure tinymce works correctly, as it did before this commit was
  introduced

Change-Id: I988f5cb76ff205d4754e57faf296c10447dd1625
Reviewed-on: https://gerrit.instructure.com/36362
Reviewed-by: Liz Abinante <labinante@instructure.com>
Reviewed-by: Cameron Sutter <csutter@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Nathan Rogowski <nathan@instructure.com>
Product-Review: Simon Williams <simon@instructure.com>