feat(openai): Response API support for reasoning summaries, stateful conversations, and Zero Data Retention (#8090)

Includes the following changes:

- Updates to latest OpenAI SDK version
- Adds `zdrEnabled` constructor option to `ChatOpenAI`, which to disables automatic `ChatOpenAI` features that depend on OpenAI data storage
- Populates [`previous_response_id`](https://platform.openai.com/docs/guides/conversation-state?api-mode=responses#openai-apis-for-conversation-state) automatically by default, unless ZDR is enabled.
- Populates the ID of previous message items when using the Responses API, unless ZDR is enabled.
- Deprecates `reasoningEffort` and `reasoning_effort` parameters in favor of the forwarded OpenAI `reasoning` object
  - These deprecated parameters are still respected if they are provided
- Adds missing fields to the `lc_serializable_keys` property
- Improves API docs to detail cases when the responses API will or won't be used.
  
Fixes #8088.

Author: benjamincburns

libs/langchain-openai/package.json

@@ -36,7 +36,7 @@
   "license": "MIT",
   "dependencies": {
     "js-tiktoken": "^1.0.12",
-    "openai": "^4.93.0",
+    "openai": "^4.96.0",
     "zod": "^3.22.4",
     "zod-to-json-schema": "^3.22.3"
   },