docs(runner): remove "the the" duplicate-word typo in AbstractChatCompletionRunner JSDoc

[devteamaegis]

Summary

Single duplicated-`the` typo in the hand-written runner helper:

```diff

• • @returns a promise that resolves with the the final assistant ChatCompletionMessage response,

• • @returns a promise that resolves with the final assistant ChatCompletionMessage response,
    ```

• `src/lib/AbstractChatCompletionRunner.ts:116` (`finalMessage` JSDoc)

Per `CONTRIBUTING.md`: "The generator will never modify the contents of the `src/lib/` and `examples/` directories" — so this file is hand-written and safe to patch directly.

Diff is exactly 1 line, JSDoc-only — no runtime/type behavior change.

Novelty

`gh search prs --repo openai/openai-node "the the final"` returns no matches. No open PR touches this line of `AbstractChatCompletionRunner.ts`.

[jbeckwith-oai]

Thanks!

[HAYDEN-OAI]

@devteamaegis thanks for catching this tiny but very real typo and sending the clean fix. appreciate your patience while we brought the branch current. merging now! 💚