Update ContextCondition::InPath to match exact path (#5938)
### Description
Updates the `ContextCondition::InPath` matching code to also accept the
exact path as "in".
| InPath | `InPath("/foo/bar")` | `InPath("/foo/bar/baz.js`") |
|---------------------|----------------------|-----------------------------|
| `"/foo/bar"` | `false` -> `true` | `false` |
| `"/foo/bar.js"` | `false` | `false` |
| `"/foo/bar/baz.js"` | `true` | `false` -> `true` |
This change is necessary to fix our `ResolveOptions` when the Next.js
entrypoint templates import the special `@vercel/turbopack/pages/_app`
module, which is import mapped to the user's `/pages/_app` file. If the
user is using `.ts` (or similar `.tsx`, etc) extensions, we need to
ensure that the default `ResolveOptions` allows this import to find the
file.
But without this change, we won't be able to prevent the
[foreign_code_context_condition](https://github.com/vercel/next.js/blob/85d30b62db4606bf56a6a9533494c9e14d55e1cc/packages/next-swc/crates/next-core/src/util.rs#L83-L101)
rule from altering our `ResolveOptions` to only import
`.js`/`.json`/`.node` files.
### Testing Instructions
Closes WEB-1544
