Fixed conditional rendering bug of submission-list

frontend/src/components/student/StudentPage.vue

@@ -5,9 +5,9 @@
           <h2>Exam Overview</h2>
           <exam-information v-if="doneLoading" :exam="exam"></exam-information>
         </v-flex>
-        <v-flex md7 offset-md1 v-if="doneLoading">
+        <v-flex md7 offset-md1>
           <h2>Submissions of {{ studentName }}</h2>
-          <submission-list :submissions="submissions"></submission-list>
+          <submission-list v-if="doneLoading" :submissions="submissions"></submission-list>
         </v-flex>
       </v-layout>
     </v-container>