Remove broken `#[turbo_tasks::value(transparent)]` attributes (#65336)
The `transparent` option only does something when the struct is a field-less unit struct with a single item.
Right now, an invalid `transparent` option is silently ignored. I'm working on a PR to change this to a compilation error, so that it's obvious that the option won't work. These are the callsites in `next.js` that my tweak brought up as potential issues.
Functionally, this PR should be a no-op.