removing top problem type UI and syncing up problem title styling with LMS conventions

TIM-270

apps/openassessment/templates/openassessmentblock/oa_base.html

 <div class="wrapper wrapper--xblock wrapper--openassessment theme--basic">
     <div class="openassessment" id="openassessment">
         <div class="wrapper--grid">
-            <h1 class="openassessment__title">
-                <span class="openassessment__title--super">
-                    {{ title }}
-                </span>
-
-                <span class="openassessment__title--sub">
-                    <span class="problem-type problem-type--open-ended-response">Open Response</span>
-                    {%  for assessment in rubric_assessments %}
-                    +
-                    <span class="problem-type problem-type--{{ assessment.type }}">{{ assessment.name }}</span>
-                    {% endfor %}
-                </span>
-            </h1>
+            <h2 class="openassessment__title ">
+                <span class="problem-header">{{ title }}</span>
+            </h2>
 
             <nav class="nav--contents">
                 <h2 class="title">Skip to a specific step:</h2>

apps/openassessment/xblock/static/sass/oa/views/_oa-base.scss

@@ -17,21 +17,10 @@
   // chrome: title
   .openassessment__title {
     @include row();
-    margin-bottom: $baseline-v;
-    border-bottom: ($baseline-v/5) solid $color-decorative-tertiary;
-    padding-bottom: ($baseline-v/2);
-  }
 
-  .openassessment__title--super {
-    @extend %hd-3;
-    display: block;
-    margin-bottom: ($baseline-v/4);
+    .problem-header {
+      text-transform: uppercase;
     }
-
-  .openassessment__title--sub {
-    @extend %hd-7;
-    display: block;
-    color: $heading-tertiary-color;
   }
 
   // steps