fix: wrap plain Error from fetch as NetworkError in React Native

[PHILLIPS71]

Description of changes

fetchTransferHandler only caught TypeError when fetch() rejected, converting it to a named NetworkError. This is correct for browsers, where the Fetch spec mandates TypeError for network failures.

React Native's native network layer throws plain Error objects instead of TypeError. These slipped through the instanceof TypeError check, were rethrown as-is, and eventually reached assertServiceError in the auth package. Because assertServiceError treats any error with name === 'Error' as an unknown failure, it wrapped them in AuthError({ name: 'Unknown' }), discarding all network error context. Callers had no way to distinguish a network failure from a genuine unexpected error.

The fix catches all non-abort errors from fetch() and wraps them as NetworkError. Aborts are explicitly re-thrown unchanged. This is safe because fetch() only rejects for two reasons: abort signals and network failures. HTTP error responses (4xx, 5xx) resolve normally and never reach the catch block.

Checklist

• PR description included
• yarn test passes
• Unit Tests are changed or added

Checklist for repo maintainers

• Verify E2E tests for existing workflows are working as expected or add E2E tests for newly added workflows
• New source file paths included in this PR have been added to CODEOWNERS, if appropriate

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

[changeset-bot]

🦋 Changeset detected

Latest commit: c35057a

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@aws-amplify/core	Patch
@aws-amplify/api-graphql	Patch
@aws-amplify/api	Patch
@aws-amplify/datastore	Patch
aws-amplify	Patch

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