fix(typescript): prevent undefined in pagination item type paths

[devin-ai-integration]

Description

Fixes a bug in the TypeScript SDK generator where pagination endpoints with optional response containers would generate invalid type signatures like undefined.List.Item.

Link to Devin run: https://app.devin.ai/sessions/64d3e6a952544a91a61aa47698a37441
Requested by: [email protected] (@tjb9dc)

Problem

When generating pagination return types for endpoints where the items array is nested under an optional property (e.g., response.data?.list where data is optional), the generator would produce invalid TypeScript:

// Before fix - INVALID TypeScript
Promise<core.Page<Agora.ListTelephonyResponse.Data | undefined.List.Item, ...>>

The issue occurred because getReferenceToResponsePropertyType() was converting a union type node like ListTelephonyResponse.Data | undefined to a string, then appending .List.Item, resulting in undefined.List.Item.

Changes Made

• Added import for removeUndefinedAndNullFromTypeNode utility
• Modified TypeContextImpl.getReferenceToResponsePropertyType() to strip undefined and null from type nodes before converting to strings for inline property type name construction
• This ensures dotted type paths like ListTelephonyResponse.Data.List.Item are built correctly without union types in the middle

Testing

⚠️ Important for reviewers:

• This fix has NOT been tested against actual SDK generation yet
• No regression test fixture was added
• Seed tests should be run to verify the fix works and doesn't break existing functionality

Recommended review steps:

1. Verify the fix resolves the issue in the agoraio-ts-sdk example
2. Run TypeScript SDK seed tests, especially pagination fixtures
3. Check if Page._getReferenceToType has similar issues
4. Consider adding a seed fixture for pagination with optional containers

Risk Assessment

• Scope: This change affects all inline property type resolution, not just pagination
• Confidence: High that this fixes the reported bug, but untested against actual generation
• Side effects: Possible edge cases where removing undefined/null from type name strings could cause issues

[devin-ai-integration]

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