fix test

Author: GoodDayForSurf

packages/devextreme-cli/testing/app-template.test.shared.js

@@ -91,6 +91,9 @@ module.exports = (env) => {
                                 await page.click('.dx-button.theme-button');
                                 await page.waitForTimeout(500);
 
+                                // eslint-disable-next-line no-undef
+                                document.querySelector('.dx-button.theme-button').blur();
+
                                 const image = await takeScreenshot();
 
                                 compareSnapshot(image, name + (mode === 'light' ? '' : '-dark'));