FIX: Query downloads were being passed an incorrect query object. (#359)

This is a follow-up to d726c4889e.

The previous change missed changing the name of the query object when passing it to QueryResultsWrapper, which resulted in the download links not working properly after a query was run.

This change fixes that bug, and includes an acceptance test to ensure it stays fixed during future work on this plugin.

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

@@ -150,11 +150,6 @@ export default class PluginsExplorerController extends Controller {
     this.showCreate = true;
   }
 
-  @action
-  resetParams() {
-    this.selectedItem.resetParams();
-  }
-
   @action
   updateSortProperty(property) {
     if (this.sortByProperty === property) {

assets/javascripts/discourse/templates/admin/plugins-explorer-queries-details.hbs

@@ -217,7 +217,7 @@
   <QueryResultsWrapper
     @results={{this.results}}
     @showResults={{this.showResults}}
-    @query={{this.selectedItem}}
+    @query={{this.model}}
     @content={{this.results}}
   />
 {{/if}}