fix: default() applies to scalars and enums, not arrays

[p5quared]

Description of changes:

The docs say that default can be applied to scalars and arrays (and not enums), but I believe it should say that it can be applied to scalars and enums (and not arrays).

e.g. this schema will not work npx ampx sandbox:

const schema = a.schema({
  Todo: a
    .model({
      content: a.integer().array().default([1, 2, 3]), // same as "[1, 2, 3]"
    })
    .authorization((allow) => [allow.publicApiKey()]),
});

// Failed to instantiate data construct
// Caused By: The @default directive may only be added to scalar or enum field types.

The actual check in @default is if (isList() || !isScalarOrEnum()) throw;

Instructions

Which product(s) are affected by this PR (if applicable)?

• amplify-cli
• amplify-ui
• amplify-studio
• amplify-hosting
• amplify-libraries

Which platform(s) are affected by this PR (if applicable)?

• JS
• Swift
• Android
• Flutter
• React Native

Please add the product(s)/platform(s) affected to the PR title
Amplify data schema

Checks

• Does this PR conform to the styleguide?

When this PR is ready to merge, please check the box below

• Ready to merge

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.