test center registration - further UI design and styling on form and dashboard tweaks

lms/static/sass/multicourse/_dashboard.scss

@@ -478,9 +478,14 @@
       .exam-registration-number {
         font-family: $sans-serif;
         font-size: 18px;
+
+        a {
+          font-family: $sans-serif;
+        }
       }
 
       &.exam-register {
+
         .message-copy {
           margin-top: 5px;
         }

lms/templates/dashboard.html

@@ -247,7 +247,7 @@
                 <div class="message message-status is-shown exam-schedule">
                 	<!-- TODO: pull Pearson destination out into a Setting -->
                    <a href="https://www1.pearsonvue.com/testtaker/signin/SignInPage/EDX" class="exam-button">Schedule Pearson exam</a>
-                   <p class="exam-registration-number">Registration number: <strong>edx00015879548</strong></p>
+                   <p class="exam-registration-number"><a href="${testcenter_register_target}" id="exam_register_link">Registration</a> number: <strong>edx00015879548</strong></p>
                    <p class="message-copy">Write this down! You’ll need it to schedule your exam.</p>
                 </div>
                 % endif