Use Quasar Vite config in Vitest

[yusufkandemir]

See quasarframework/quasar#17685

In app-vite v3, it would be like:

import { getTestingConfig } from '@quasar/app-vite/testing'

export default defineConfig(async () => ({
  resolve: {
    alias: (await getTestingConfig()).resolve.alias,
  },
}))

This solution can be generalized to apply to stuff other than just resolve.alias, can be put in a wrapper, etc. as needed.