fix: auto generate types faster and more reliably to avoid issues when spawning processes

[r1tsuu]

Fixes #11276

Previously, to auto generate types on HMR and startup we spawned a child process with the payload generate:types command.
This, potentially can cause some issues in monorepos (our Astro and Remix examples, as described in #11276) and whenever payload config path cannot be determined (as it's necessary for payload.bin) It's also faster to execute generateTypes directly.

Nevertheless, it was a necessary change because of a turbopack issue #6714 vercel/next.js#66723

The issue now looks resolved, I tested against the latest next.js canary with a packed payload version from this PR and types auto-generation works correctly using pnpm dev --turbo.

Other changes were necessary to pass integration and unit tests Apparently, as jest isn't executed in a proper ESM environment, it requires to use --experimental-vm-modules to be able to load json-schema-to-typescript.