fix new module IE 10 dialog form submit on enter

test plan:

* in a course that already has one or more modules,
 use IE 10 toopen the "create module" dialog to add a module
 to a course
* with keyboard focus on the module name text field,
 press enter
* should submit the module as in other browsers

fixes #CNVS-14224

Change-Id: I1952c3d60e1ad05dfd4ea5962218f09dd2d21d5f
Reviewed-on: https://gerrit.instructure.com/37979
Reviewed-by: Ryan Shaw <ryan@instructure.com>
QA-Review: Clare Strong <clare@instructure.com>
Tested-by: Jenkins <jenkins@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>