delete unused config

packages/remark-growi-directive/vitest.config.ts

@@ -1,13 +0,0 @@
-import tsconfigPaths from 'vite-tsconfig-paths';
-import { defineConfig } from 'vitest/config';
-
-export default defineConfig({
-  plugins: [
-    tsconfigPaths(),
-  ],
-  test: {
-    environment: 'node',
-    clearMocks: true,
-    globals: true,
-  },
-});