Replace v-html with gl-icon in ee/.../add_gitlab_slack_application.vue

Signed-off-by: Takuya Noguchi <takninnovationresearch@gmail.com>

ee/app/assets/javascripts/add_gitlab_slack_application/components/add_gitlab_slack_application.vue

 <script>
-/* eslint-disable @gitlab/vue-require-i18n-strings, vue/no-v-html */
-import { GlButton } from '@gitlab/ui';
+/* eslint-disable @gitlab/vue-require-i18n-strings */
+import { GlButton, GlIcon } from '@gitlab/ui';
 import { __ } from '~/locale';
 import { deprecatedCreateFlash as Flash } from '~/flash';
 import { redirectTo } from '~/lib/utils/url_utility';
-import { spriteIcon } from '~/lib/utils/common_utils';
 
 import GitlabSlackService from '../services/gitlab_slack_service';
 
 export default {
   components: {
     GlButton,
+    GlIcon,
   },
 
   props: {
@@ -64,14 +64,6 @@ export default {
   },
 
   computed: {
-    doubleHeadedArrowSvg() {
-      return spriteIcon('double-headed-arrow');
-    },
-
-    arrowRightSvg() {
-      return spriteIcon('arrow-right');
-    },
-
     hasProjects() {
       return this.projects.length > 0;
     },
@@ -98,10 +90,10 @@ export default {
 
     <div v-once class="prepend-top-20 append-bottom-20">
       <img :src="gitlabLogoPath" class="gitlab-slack-logo" />
-      <div
+      <gl-icon
+        name="double-headed-arrow"
         class="gitlab-slack-double-headed-arrow inline prepend-left-20 append-right-20"
-        v-html="doubleHeadedArrowSvg"
-      ></div>
+      />
       <img :src="slackLogoPath" class="gitlab-slack-logo" />
     </div>
 
@@ -159,7 +151,7 @@ export default {
           >/gitlab &lt;project-alias&gt; issue show &lt;id&gt;</code
         >
         <span>
-          <div class="gitlab-slack-right-arrow inline gl-mr-2" v-html="arrowRightSvg"></div>
+          <gl-icon name="arrow-right" class="gitlab-slack-right-arrow inline gl-mr-2" />
           Shows the issue with id <strong>&lt;id&gt;</strong>
         </span>