[Bug]: npm_typescript extension prone to misuse

### What happened?

It has the problem that users aren't specifying a non-default name, which results in conflicts
as observed on https://github.com/google/flatbuffers/pull/8561

per @fmeum: Since the extension doesn't perform version resolution, it would be better to have it fail when used by a non-root module so that users are forced to make it a dev_dependency (if that's not okay for backwards compatibility, ignore it instead)

### Version

Development (host) and target OS/architectures:

Output of `bazel --version`:

Version of the Aspect rules, or other relevant rules from your
`WORKSPACE` or `MODULE.bazel` file:

Language(s) and/or frameworks involved:

### How to reproduce

```shell

```

### Any other information?

_No response_

Start by reading the npm_typescript extension and the conflict described in pull request 8561; compare behavior when it is used by a non-root module. Done means the extension prevents or ignores the unsafe non-root use while preserving the intended root-module behavior and accounting for backwards compatibility.

Written by the indexing model from the issue text.