When creating a type with a sort key on the id field, codegen is making id required

### Amplify CLI Version

12.1.1

### Question

When creating a type in schema.graphql like this

```ts
type NodeModel
@model
@auth(rules: [{ allow: private}])
{
id: ID! @primaryKey
...
}
```
codegen creates a type like this:

```ts
type LazyNodeModel = {
readonly [__modelMeta__]: {
identifier: OptionallyManagedIdentifier;
};
readonly id: string;
...
}
```
Which allows me to do:

```ts
const node = new NodeModel({
// id not required
// other fields...
})
```

The ID is not required.

But if I add a sort key to the primary key like this:

```ts
type NodeModel
@model
@auth(rules: [{ allow: private}])
{
id: ID! @primaryKey(sortKeyFields: ["someOtherID"])
...
}
```

The generated type is:

```ts
type LazyNodeModel = {
readonly [__modelMeta__]: {
identifier: CompositeIdentifier;
};
readonly id: string;
...
}
```
And when I try to do:
```ts
const node = new NodeModel({
id: 'some-value', // typescript complains if I don't add this
// other fields...
});
```

It's requiring that I specify the ID myself.

Is this a bug or am I misusing the @primarayKey and sortKeyFields directives?

Start with the schema.graphql examples and compare the generated LazyNodeModel and NodeModel types for primary keys with and without sortKeyFields. Trace the codegen path that determines whether id is optional, then verify that a composite primary key still permits the shown constructor usage and add coverage for both schemas if the repository provides a suitable test entry point.

Written by the indexing model from the issue text.