Try fix snapshot taken when export button is in loading stat

app/templates/app/generator.hbs

@@ -54,9 +54,10 @@
         width="full"
         scale="l"
         disabled={{this.exportDisabled}}
-        loading={{this.meshGenerating}}
+        loading={{true}}
         icon-start="download"
         {{on 'click' this.exportSTL}}
+        data-test-export-stl
       >
         {{t 'export_stl'}}
       </calcite-button>

tests/acceptance/visual-test.ts

@@ -1,6 +1,6 @@
 /* eslint-disable no-await-in-loop */
 import { module, test } from 'qunit';
-import { visit } from '@ember/test-helpers';
+import { visit, waitFor } from '@ember/test-helpers';
 import { setupApplicationTest } from 'ember-qunit';
 import testsSettings from './_tests-settings';
 import percySnapshot from '@percy/ember';
@@ -22,10 +22,7 @@ module('Acceptance | visual', function (hooks) {
       // Load test settings through QP
       await visit(`/en-us/generator?modelSettings=${settingsQP}`);
       await waitCalciteReady();
-
-      await new Promise(function (resolve) {
-        setTimeout(resolve, 250);
-      });
+      await waitFor('[data-test-export-stl]:not([loading])');
       await percySnapshot(`visual test #${testIdx + 1}`);
       assert.true(true);
     });