test: fix to namespaced import to cause tests to pass

Author: brettz9

test/prettier.mjs

@@ -24,7 +24,7 @@ import eslintPluginSvelte from 'eslint-plugin-svelte';
 import eslintPluginPug from 'eslint-plugin-pug';
 import vueEslintParser from 'vue-eslint-parser';
 import * as eslintPluginGraphql from '@graphql-eslint/eslint-plugin';
-import eslintMdx from 'eslint-mdx';
+import * as eslintMdx from 'eslint-mdx';
 import eslintPluginJson from '@eslint/json';
 
 const rule = eslintPluginPrettier.rules.prettier;