added id of button needed for test

small change

frontend/src/components/submission_notes/base/SubmissionLine.vue

@@ -51,8 +51,7 @@ export default {
   data () {
     return {
       key: 0,
-      html:'',
-      markdowned:true
+      html:''
     }
   },
   computed: {

frontend/src/components/submission_notes/toolbars/ToggleFeedbackVisibilityButton.vue

 <template>
   <v-btn
     v-if="showFeedback"
+    id="feedback-visibility-toggle"
     text
     color="info"
     title="Feedback is being shown"
@@ -13,6 +14,7 @@
   </v-btn>
   <v-btn
     v-else
+    id="feedback-visibility-toggle"
     text
     color="grey"
     title="Feedback is not being shown"