Fix a11y tests

Author: alex-page

polaris-react/package.json

@@ -82,7 +82,7 @@
     "@shopify/jest-dom-mocks": "^3.0.5",
     "@shopify/postcss-plugin": "^5.0.1",
     "@shopify/react-testing": "^3.2.4",
-    "@shopify/storybook-a11y-test": "1.0.1",
+    "@shopify/storybook-a11y-test": "0.4.3",
     "@storybook/addon-a11y": "^6.5.9",
     "@storybook/addon-toolbars": "^6.5.9",
     "@storybook/builder-webpack5": "^6.5.9",