fix: Update Google Cloud Enterprise Search to Vertex AI Search (#10513)

- Description: Google Cloud Enterprise Search was renamed to Vertex AI
Search
-
https://cloud.google.com/blog/products/ai-machine-learning/vertex-ai-search-and-conversation-is-now-generally-available
- This PR updates the documentation and Retriever class to use the new
terminology.
- Changed retriever class from `GoogleCloudEnterpriseSearchRetriever` to
`GoogleVertexAISearchRetriever`
- Updated documentation to specify that `extractive_segments` requires
the new [Enterprise
edition](https://cloud.google.com/generative-ai-app-builder/docs/about-advanced-features#enterprise-features)
to be enabled.
  - Fixed spelling errors in documentation.
- Change parameter for Retriever from `search_engine_id` to
`data_store_id`
- When this retriever was originally implemented, there was no
distinction between a data store and search engine, but now these have
been split.
- Fixed an issue blocking some users where the api_endpoint can't be set

docs/docs_skeleton/vercel.json

@@ -3739,6 +3739,10 @@
     {
       "source": "/docs/ecosystem/dependents",
       "destination": "/docs/additional_resources/dependents"
+    },
+    {
+      "source": "docs/integrations/retrievers/google_cloud_enterprise_search",
+      "destination": "docs/integrations/retrievers/google_vertex_ai_search"
     }
   ]
-}
+}