Notes css is missing for tab pages (#21846)

style-student-notes is only added in courseware.html but it is missing
for custom tab pages.

PROD-687

lms/templates/courseware/static_tab.html

@@ -25,6 +25,7 @@ ${HTML(fragment.foot_html())}
 <%block name="pagetitle">${_(tab['name'])} | ${course.display_number_with_default}</%block>
 
 <%include file="/courseware/course_navigation.html" args="active_page=active_page" />
+<%static:css group='style-student-notes'/>
 
 <main id="main" aria-label="Content" tabindex="-1">
     <section class="container"