Update alert to gl component

app/assets/javascripts/ide/components/terminal/empty_state.vue

 <script>
 /* eslint-disable vue/no-v-html */
-import { GlLoadingIcon, GlButton } from '@gitlab/ui';
+import { GlLoadingIcon, GlButton, GlAlert, } from '@gitlab/ui';
 
 export default {
   components: {
     GlLoadingIcon,
     GlButton,
+    GlAlert,
   },
   props: {
     isLoading: {
@@ -59,7 +60,7 @@ export default {
           {{ __('Start Web Terminal') }}
         </gl-button>
       </p>
-      <div v-if="!isValid && message" class="bs-callout gl-text-left" v-html="message"></div>
+      <gl-alert v-if="!isValid && message" variant="tip" :dismissable="false" v-html="message"></gl-alert>
       <p v-else>
         <a
           v-if="helpPath"