Currently the interop resulting target of a `ts_project` ends up not
necessarily working at runtime. This may be the case because a consuming
Node program may end up with mixes of `node_modules` dependencies from
`rules_nodejs` (old) and `rules_js` (new). This sounds fine at first
glance, but in practice can break very subtly because:

* Rules NodeJS leverages the linker, creating `node_module` directories
  outside of Bazel, at runtime. These don't depend on symlink resolving.
* Rules JS puts real node module folders via Bazel actions. These rely
  on `pnpm` non-hoisting layout, and symlink resolving.

As we can see there is a hard conflict with symlinks. They need to be
enabled with the new toolchain, but the other one doesn't enable symlink
resolution, and enabling is not possible as we'd otherwise risk escaping
the sandbox and cause even more subtle errors.

A good compromise solution is to automatically drop the `rules_js` node
module files/folder in the interop-`rules_nodejs` target and instead
brining in the equivalent `@npm//` dependencies from `rules_nodejs`.
This kind of keeps the logic similar to when not using `rules_js` or the
interop, and enables the simplest & safest mental model; and it works
compared to other solutions I tried with symlinking. Notably, we can't
keep both node module variants as the linker doesn't override existing
node module files from e.g. rules_js then (and would break then).