[Turbopack] use file.read() instead of file.track() in webpack loaders (#69659)
### What?
`track()` invalidates based on watcher events and might have false
invalidation when events occur but files do not actually change. This
also happens when restoring from persistent caching where all files are
considered as changed.
`read()` invalidates only when the file content actually changed.
Since webpack loaders are usually pretty expensive we want to use
`read()` instead of `track()` here.