show "user account details" button based on permissions

they should already be able to visit the page, this
just shows the link

test plan:
* create a sub account admin with the right to
 "View Statistics"
* should be able to see the "User Account Details"
 button on a course users page (/courses/X/users/Y)

closes #CNVS-17411

Change-Id: I26fd5f69449d7ebb4f128d46077926efb09e0394
Reviewed-on: https://gerrit.instructure.com/45693
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Dan Minkevitch <dan@instructure.com>
QA-Review: Jahnavi Yetukuri <jyetukuri@instructure.com>
Product-Review: James Williams  <jamesw@instructure.com>