fix(typescript): choose the correct snippet for readme

[dsinghvi]

Description

Updates the TypeScript generator to correctly pick snippets for streaming/pagination.

Changes Made

• Update TypeScript generator to find streaming/pagination specific endpoints
• Use the endpoints above for snippets
• Don't fail the generator if the snippet is present so that we still generate an SDK

Testing

Manually tested on fern definitions + seed

[github-actions[bot]]

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