Replace icons in IssueCardInner vue component

app/assets/javascripts/boards/components/issue_card_inner.vue

 <script>
   import $ from 'jquery';
   import IssueCardWeight from 'ee/boards/components/issue_card_weight.vue';
+  import Icon from '~/vue_shared/components/icon.vue';
   import UserAvatarLink from '../../vue_shared/components/user_avatar/user_avatar_link.vue';
   import eventHub from '../eventhub';
   import tooltip from '../../vue_shared/directives/tooltip';
@@ -10,6 +11,7 @@
     components: {
       UserAvatarLink,
       IssueCardWeight,
+      Icon,
     },
     directives: {
       tooltip,
@@ -142,11 +144,12 @@
   <div>
     <div class="board-card-header">
       <h4 class="board-card-title">
-        <i
+        <icon
           v-if="issue.confidential"
-          class="fa fa-eye-slash confidential-icon"
+          name="eye-slash"
           aria-hidden="true"
-        ></i>
+          class="confidential-icon"
+        />
         <a
           :href="issue.path"
           :title="issue.title"

app/assets/stylesheets/pages/boards.scss

@@ -350,8 +350,7 @@
   }
 
   .confidential-icon {
-    position: relative;
-    top: 1px;
+    vertical-align: text-top;
     margin-right: 5px;
   }
 }