serveStaticMiddleware should not fail when allow is configured

[benmccann]

Describe the bug

I would like to only allow serving of the publicDir in SvelteKit via the allow method. However, it looks like root is always served

vite/packages/vite/src/node/server/index.ts

Line 528 in 1f4723b

middlewares.use(serveStaticMiddleware(root, server))

When I set server.fs.allow to only allow serving the static directory that causes all requests to fail since serveStaticMiddleware is serving the root directory and will fail the access check

Reproduction

npm init svelte@next my-app
cd my-app
npm install

Set kit.vite.server.fs.allow equal to kit.files.assets (i.e. ['static']) and then run npm run dev

System Info

Vite 2.6.11

Used Package Manager

npm

Logs

Browser gives 403 error

Validations

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