Improve types for GraphQLResult errors

[neilime]

Issue #, if available:

import { GraphQLResult } from '@aws-amplify/api-graphql';

const result = { errors: [{ message: 'test' }] } as GraphQLResult;

if (result.errors) {
  console.log(result.errors[0].message); 
  // Typescript error `Property 'message' does not exist on type 'object'`
}

Description of changes:

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

[codecov]

Codecov Report

Merging #5994 into main will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #5994   +/-   ##
=======================================
  Coverage   73.31%   73.31%           
=======================================
  Files         208      208           
  Lines       12922    12922           
  Branches     2433     2433           
=======================================
  Hits         9474     9474           
  Misses       3285     3285           
  Partials      163      163           

Impacted Files	Coverage Δ
packages/api-graphql/src/types/index.ts	100.00% <ø> (ø)

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[amhinson]

Thanks @neilime! 🙏

[github-actions]

This pull request has been automatically locked since there hasn't been any recent activity after it was closed. Please open a new issue for related bugs.

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