fix(glue-alpha): omit comments from struct type strings

[sjh9714]

Issue # (if applicable)

Closes #26935.

Reason for this change

Schema.struct() rendered COMMENT '...' inside the generated nested struct type string when a struct field had a comment. Glue/Athena do not support COMMENT inside nested type definitions, so the resulting inputString could not be used for nested schemas.

Description of changes

This removes comment rendering from the Schema.struct() type string. Column comments remain available on Column objects for top-level table columns, where they are represented separately by Glue's Comment property rather than embedded in a nested type string.

The existing schema unit test now covers the reported case by asserting that comments on struct fields are not emitted into nested inputString values.

Describe any new or updated permissions being added

None.

Description of how you validated changes

Before the implementation change, yarn test in packages/@aws-cdk/aws-glue-alpha failed in test/schema.test.ts because the struct inputString still included nested COMMENT clauses.

Commands run:

• yarn install --frozen-lockfile
• npx lerna run build --scope @aws-cdk/aws-glue-alpha --include-dependencies --skip-nx-cache
• yarn build from packages/@aws-cdk/aws-glue-alpha
• yarn test from packages/@aws-cdk/aws-glue-alpha
• git diff --check

Note: I used Codex while preparing this change and reviewed the final diff and local verification.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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

[aws-cdk-automation]

The pull request linter fails with the following errors:

❌ Fixes must contain a change to an integration test file and the resulting snapshot.

If you believe this pull request should receive an exemption, please comment and provide a justification. A comment requesting an exemption should contain the text Exemption Request. Additionally, if clarification is needed, add Clarification Request to a comment.

✅ A exemption request has been requested. Please wait for a maintainer's review.

[sjh9714]

Exemption Request:

This fix changes only Schema.struct() input string rendering for nested Glue struct field comments. It is covered by the existing schema.test.ts unit coverage, and it does not change synthesized CloudFormation resources or integration snapshots.

I ran yarn test in packages/@aws-cdk/aws-glue-alpha; the package tests passed and all integration snapshots were reported as unchanged.