Convert Threat Monitoring environment picker to GlDropdown

Convert the dropdown from GlDeprecatedDropdown to GlDropdown

changelogs/unreleased/cngo-convert-threat-monitoring-environment-picker-to-gl-dropdown.yml

+---
+title: Convert Threat Monitoring environment picker to GlDropdown
+merge_request: 54309
+author:
+type: changed

ee/app/assets/javascripts/threat_monitoring/components/environment_picker.vue

 <script>
-import { GlFormGroup, GlDeprecatedDropdown, GlDeprecatedDropdownItem } from '@gitlab/ui';
+import { GlFormGroup, GlDropdown, GlDropdownItem } from '@gitlab/ui';
 import { mapActions, mapGetters, mapState } from 'vuex';
 import { ALL_ENVIRONMENT_NAME } from '../constants';
 
 export default {
   components: {
     GlFormGroup,
-    GlDeprecatedDropdown,
-    GlDeprecatedDropdownItem,
+    GlDropdown,
+    GlDropdownItem,
   },
   props: {
     includeAll: {
@@ -40,27 +40,27 @@ export default {
     :label-for="$options.environmentFilterId"
     class="col-sm-6 col-md-4 col-lg-3 col-xl-2"
   >
-    <gl-deprecated-dropdown
+    <gl-dropdown
       :id="$options.environmentFilterId"
       ref="environmentsDropdown"
-      class="mb-0 d-flex"
-      toggle-class="d-flex justify-content-between text-truncate"
+      class="gl-display-flex"
+      toggle-class="gl-truncate"
       :text="environmentName"
       :disabled="!canChangeEnvironment"
     >
-      <gl-deprecated-dropdown-item
+      <gl-dropdown-item
         v-for="environment in environments"
         :key="environment.id"
         ref="environmentsDropdownItem"
         @click="setCurrentEnvironmentId(environment.id)"
-        >{{ environment.name }}</gl-deprecated-dropdown-item
+        >{{ environment.name }}</gl-dropdown-item
       >
-      <gl-deprecated-dropdown-item
+      <gl-dropdown-item
         v-if="includeAll"
         ref="environmentsDropdownItem"
         @click="setAllEnvironments"
-        >{{ $options.ALL_ENVIRONMENT_NAME }}</gl-deprecated-dropdown-item
+        >{{ $options.ALL_ENVIRONMENT_NAME }}</gl-dropdown-item
       >
-    </gl-deprecated-dropdown>
+    </gl-dropdown>
   </gl-form-group>
 </template>