Improve course breadcrumbs

LEARNER-877

common/static/common/templates/sequence-breadcrumbs.underscore

@@ -1,9 +0,0 @@
-<% if (unifiedCourseView) { %>
-    <a href="<%- '/courses/' + courseId + '/course/#' + blockId %>">
-        <span class="fa fa-arrow-circle-prev icon" aria-hidden="true" aria-describedby="outline-description"></span>
-        <span class="sr-only" id="outline-description"><%- gettext('Return to course outline') %></span>
-        <b><%- gettext('Outline') %></b>
-    </a>
-    <span> > </span>
-<% } %>
-<span class="position"><%- pathText %></span>