fix(amplify-category-storage): make IAM policy names environment-specific

[w3lld1]

Description of changes

I made generated S3 IAM policy names environment-specific by appending the current Amplify environment name to the existing policy UUID. This prevents two environments that share imported auth roles from trying to manage identically named inline policies.

I also added a focused regression test for the generated policy names and updated the existing stack-transform expectations.

Issue #, if available

Fixes #14961

Description of how you validated changes

• yarn lerna run build --scope @aws-amplify/amplify-category-storage --include-dependencies --concurrency 4
• node ../../node_modules/jest/bin/jest.js --runInBand --coverage=false from packages/amplify-category-storage (15 suites, 48 tests)
• Prettier and ESLint checks for all changed TypeScript files

I did not run cloud E2E tests or the macOS CI job locally.

Checklist

• PR description included
• yarn test passes for the changed package
• Tests are changed or added
• Relevant documentation is changed or added (and PR referenced)
• New AWS SDK calls or CloudFormation actions have been added to relevant test and service IAM policies
• Pull request labels are added

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