fix todo list stretched by long submission comments
fix todo list stretched by long submission comments

fixes CNVS-32407

test plan:
- leave a long comment on a speed grader submission (>= 140 chars)
- masquerade as the student and notice on the dashboard that the
 comment wraps around multiple lines of text instead of stretching
 the sidebar or the todo list

Change-Id: I2ac4937f13f03fa1015b4570efef9e185e751c0e
Reviewed-on: https://gerrit.instructure.com/94773
Tested-by: Jenkins
Reviewed-by: Frederick Polgardy <ab16c4039c093a54edcd45187f296bbb40221556@instructure.com>
QA-Review: David Tan <6283e310a2278fc51bdc4fb5974f70dd9c3366b9@instructure.com>
Product-Review: Felix Milea-Ciobanu <9384aa226ac9d3237ed0bc52e18ffcb251ee0bf7@instructure.com>

grahamb/canvas-lms,sfu/canvas-lms,djbender/canvas-lms,matematikk-mooc/canvas-lms,matematikk-mooc/canvas-lms,instructure/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,venturehive/canvas-lms,matematikk-mooc/canvas-lms,djbender/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,sfu/canvas-lms,venturehive/canvas-lms,grahamb/canvas-lms,SwinburneOnline/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,djbender/canvas-lms,instructure/canvas-lms,SwinburneOnline/canvas-lms,instructure/canvas-lms,matematikk-mooc/canvas-lms,grahamb/canvas-lms,djbender/canvas-lms,SwinburneOnline/canvas-lms,sfu/canvas-lms,sfu/canvas-lms,instructure/canvas-lms,sfu/canvas-lms,instructure/canvas-lms