fix module item indentation

fixes CNVS-12368

Indenting module items should all line up

Test Plan

As a teacher or student
Given I have a module item that is indented
And it has completion requirements

When I view the modules page or homepage with module items
Then the module item title should be indented
And the module item icon should be indented
And the module item descriptions should be indented

Change-Id: I9908befe3fdcc871693e6eaacdc1a2cf5791279b
Reviewed-on: https://gerrit.instructure.com/33244
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: Hilary Scharton <hilary@instructure.com>
Reviewed-by: Jeremy Stanley <jeremy@instructure.com>
QA-Review: Matt Fairbourn <mfairbourn@instructure.com>