Allow dependencies to use environment variables in middlewares (#33141)
After discussing with @sokra, seems that the proposed solution is split in two:
* We need to make sure that the `process` polyfill uses `global.process` if available. This is because middlewares are bundled using `browser` target and therefore `process.env.MY_ENV` gets shimmed into `require('process').env.MY_ENV`.
* Allow `process.env` to be statically analyzed for dependencies so they will be exported to the manifest.
Related issues:
* should fix #33043.