Add OverrideDropdown to toggle state

app/assets/javascripts/integrations/edit/components/integration_form.vue

 <script>
+import { mapState } from 'vuex';
 import glFeatureFlagsMixin from '~/vue_shared/mixins/gl_feature_flags_mixin';
+
+import OverrideDropdown from './override_dropdown.vue';
 import ActiveToggle from './active_toggle.vue';
 import JiraTriggerFields from './jira_trigger_fields.vue';
 import JiraIssuesFields from './jira_issues_fields.vue';
@@ -9,6 +12,7 @@ import DynamicField from './dynamic_field.vue';
 export default {
   name: 'IntegrationForm',
   components: {
+    OverrideDropdown,
     ActiveToggle,
     JiraTriggerFields,
     JiraIssuesFields,
@@ -49,6 +53,7 @@ export default {
     },
   },
   computed: {
+    ...mapState(['overrideAvailable']),
     isJira() {
       return this.type === 'jira';
     },
@@ -61,6 +66,7 @@ export default {
 
 <template>
   <div>
+    <override-dropdown v-if="overrideAvailable" />
     <active-toggle v-if="showActive" v-bind="activeToggleProps" />
     <jira-trigger-fields v-if="isJira" v-bind="triggerFieldsProps" />
     <trigger-fields v-else-if="triggerEvents.length" :events="triggerEvents" :type="type" />

app/assets/javascripts/integrations/edit/components/override_dropdown.vue

+<script>
+import { __ } from '~/locale';
+import { mapState } from 'vuex';
+import { GlNewDropdown, GlNewDropdownItem } from '@gitlab/ui';
+
+const options = [
+  {
+    value: 'instance',
+    text: __('Use instance level settings'),
+  },
+  {
+    value: 'project',
+    text: __('Use custom settings'),
+  },
+];
+
+const defaultOption = options[0];
+const customOption = options[1];
+
+export default {
+  name: 'OverrideDropdown',
+  components: {
+    GlNewDropdown,
+    GlNewDropdownItem,
+  },
+  props: {},
+  data() {
+    return {
+      options,
+      selected: defaultOption,
+    };
+  },
+  computed: {
+    ...mapState(['override']),
+  },
+  methods: {
+    onClick(option) {
+      this.selected = option;
+      this.$store.dispatch('setOverride', option === customOption);
+    },
+  },
+};
+</script>
+
+<template>
+  <div
+    class="gl-display-flex gl-justify-content-space-between gl-align-items-baseline gl-py-4 gl-mt-5 gl-mb-6 gl-border-t-1 gl-border-t-solid gl-border-b-1 gl-border-b-solid gl-border-gray-100"
+  >
+    <span>{{ __('This integration has multiple settings available.') }}</span>
+    <gl-new-dropdown :text="selected.text">
+      <gl-new-dropdown-item v-for="option in options" :key="option.value" @click="onClick(option)">
+        {{ option.text }}
+      </gl-new-dropdown-item>
+    </gl-new-dropdown>
+  </div>
+</template>