DataSchema breaks if updatedAt/createdAt are not defined in the model when creating secondaryIndex with sortKeys with them

### Environment information

```plain text
System:
OS: macOS 14.5
CPU: (8) arm64 Apple M1
Memory: 143.28 MB / 16.00 GB
Shell: /bin/zsh
Binaries:
Node: 20.12.1 - ~/.nvm/versions/node/v20.12.1/bin/node
Yarn: undefined - undefined
npm: 10.5.0 - ~/.nvm/versions/node/v20.12.1/bin/npm
pnpm: undefined - undefined
NPM Packages:
@aws-amplify/backend: 1.0.2
@aws-amplify/backend-cli: 1.0.3
aws-amplify: 6.3.4
aws-cdk: 2.141.0
aws-cdk-lib: 2.141.0
typescript: 5.4.5
AWS environment variables:
AWS_STS_REGIONAL_ENDPOINTS = regional
AWS_NODEJS_CONNECTION_REUSE_ENABLED = 1
AWS_SDK_LOAD_CONFIG = 1
No CDK environment variables
```

### Data packages

```plain text
├─┬ @aws-amplify/backend-cli@1.0.3
│ └─┬ @aws-amplify/schema-generator@1.0.0
│ └── @aws-amplify/graphql-schema-generator@0.8.5
└─┬ @aws-amplify/backend@1.0.2
└─┬ @aws-amplify/backend-data@1.0.1
└── @aws-amplify/data-construct@1.8.2
```

### Description

In the docs: https://docs.amplify.aws/react/build-a-backend/data/mutate-data/#create-an-item says:

Note: You do not need to specify createdAt or updatedAt fields because Amplify automatically populates these fields for you.

But if you don't declare them, the lint breaks if you want to use them as sortKeys, so I had to declare both of them to be able to use as sortKeys. and it also broke the auto complete for my models list methods.

for example:
```
const schema = a.schema({
Privacy: a.enum(['public', 'private', 'shared']),
MyModel: a
.model({
ownerUserId: a.id().required(),
name: a.string(),
privacy: a.ref('Privacy'),
})
.secondaryIndexes((index) => [
index('ownerUserId').name('byOwner').sortKeys(['updatedAt']),
]),
});
```
So it auto generated the following query so to be used in the frontend:
```
client.models.MyModel.listCreativeMetaByOwnerUserId({
ownerUserId: 'USER_ID_HERE'
});
```

It shows this error:
```
error TS2322: Type '"updatedAt"' is not assignable to type '"name" | "ownerUserId" | "privacy"'.
TypeScript validation check failed.
Resolution: Fix the syntax and type errors in your backend definition.
```

To by pass this I had to add updatedAt and created to my model:
```
const schema = a.schema({
Privacy: a.enum(['public', 'private', 'shared']),
MyModel: a
.model({
updatedAt: a.datetime(),
createdAt: a.datetime(),
ownerUserId: a.id().required(),
name: a.string(),
privacy: a.ref('Privacy'),
})
.secondaryIndexes((index) => [
index('ownerUserId').name('byOwner').sortKeys(['updatedAt']),
]),
});
```

So it auto generated the following query so to be used in the frontend:
```
client.models.MyModel.listCreativeMetaByOwnerUserIdAndUpdatedAt({
ownerUserId: 'USER_ID_HERE'
});
```

And then it works as intended.

Just wanna check if this is the intended behaviour or if im missing something.

Start with the DataSchema secondaryIndexes path and the generated model list typings, comparing a model that declares updatedAt and createdAt with one that relies on automatic timestamps. Reproduce the TypeScript error using the provided schema and verify that sortKeys accepts the automatic timestamp fields and generates the corresponding list method types.

Written by the indexing model from the issue text.