DEV: Update modal to component API (#269)

<img width="622" alt="Screenshot 2023-12-06 at 12 10 09 PM" src="https://github.com/discourse/discourse-data-explorer/assets/50783505/5a6fb0b2-829c-4af3-93c9-91676b78ab59">

assets/javascripts/discourse/components/modal/query-help.gjs

@@ -0,0 +1,19 @@
+import DModal from "discourse/components/d-modal";
+import htmlSafe from "discourse-common/helpers/html-safe";
+import i18n from "discourse-common/helpers/i18n";
+
+const QueryHelp = <template>
+  <DModal
+    @title={{i18n "explorer.help.modal_title"}}
+    @closeModal={{@closeModal}}
+  >
+    <:body>
+      {{htmlSafe (i18n "explorer.help.auto_resolution")}}
+      {{htmlSafe (i18n "explorer.help.custom_params")}}
+      {{htmlSafe (i18n "explorer.help.default_values")}}
+      {{htmlSafe (i18n "explorer.help.data_types")}}
+    </:body>
+  </DModal>
+</template>;
+
+export default QueryHelp;

assets/javascripts/discourse/controllers/admin-plugins-explorer.js

@@ -5,14 +5,15 @@ import { inject as service } from "@ember/service";
 import { Promise } from "rsvp";
 import { ajax } from "discourse/lib/ajax";
 import { popupAjaxError } from "discourse/lib/ajax-error";
-import showModal from "discourse/lib/show-modal";
 import { bind } from "discourse-common/utils/decorators";
 import I18n from "I18n";
+import QueryHelp from "discourse/plugins/discourse-data-explorer/discourse/components/modal/query-help";
 import Query from "discourse/plugins/discourse-data-explorer/discourse/models/query";
 
 const NoQuery = Query.create({ name: "No queries", fake: true, group_ids: [] });
 
 export default class PluginsExplorerController extends Controller {
+  @service modal;
   @service dialog;
   @service appEvents;
   @service router;
@@ -270,7 +271,7 @@ export default class PluginsExplorerController extends Controller {
 
   @action
   showHelpModal() {
-    showModal("query-help");
+    this.modal.show(QueryHelp);
   }
 
   @action