Reenable course home improvements check.

This was disabled some time ago due to PLAT-900, which caused cached
objects to be unpickled and used in new code which could expect to
find new fields that didn't exist on the old objects. That issue is
now fixed.

ECOM-2853

lms/templates/courseware/info.html

@@ -61,7 +61,7 @@ $(document).ready(function(){
       ${get_course_info_section(request, masquerade_user, course, 'updates')}
     </section>
     <section aria-label="${_('Handout Navigation')}" class="handouts">
-      % if False:
+      % if SelfPacedConfiguration.current().enable_course_home_improvements:
         <h1>${_("Important Course Dates")}</h1>
         ${get_course_date_summary(course, user)}
       % endif