Remove VertexAI GCP SDK API and deprecate unsupported models.

We fully turn to REST API.

Note that the deprecated model (mainly old palm models) is not supported with SDK API anymore either.

PiperOrigin-RevId: 702202962

README.md

@@ -140,7 +140,6 @@ If you want to customize your installation, you can select specific features usi
 | all                 | All Langfun features.                    |
 | llm                 | All supported LLMs.                      |
 | llm-google          | All supported Google-powered LLMs.       |
-| llm-google-vertexai | LLMs powered by Google Cloud VertexAI    |
 | llm-google-genai    | LLMs powered by Google Generative AI API |
 | mime                | All MIME supports.                       |
 | mime-auto           | Automatic MIME type detection.           |

langfun/core/llms/__init__.py

@@ -120,25 +120,19 @@
 from langfun.core.llms.groq import GroqWhisper_Large_v3Turbo
 
 from langfun.core.llms.vertexai import VertexAI
-from langfun.core.llms.vertexai import VertexAIRest
-from langfun.core.llms.vertexai import VertexAIRestGemini1_5
 from langfun.core.llms.vertexai import VertexAIGemini1_5
 from langfun.core.llms.vertexai import VertexAIGeminiPro1_5
-from langfun.core.llms.vertexai import VertexAIGeminiPro1_5_Latest
 from langfun.core.llms.vertexai import VertexAIGeminiPro1_5_001
 from langfun.core.llms.vertexai import VertexAIGeminiPro1_5_002
 from langfun.core.llms.vertexai import VertexAIGeminiPro1_5_0514
 from langfun.core.llms.vertexai import VertexAIGeminiPro1_5_0409
-from langfun.core.llms.vertexai import VertexAIGeminiFlash1_5_Latest
 from langfun.core.llms.vertexai import VertexAIGeminiFlash1_5
 from langfun.core.llms.vertexai import VertexAIGeminiFlash1_5_001
 from langfun.core.llms.vertexai import VertexAIGeminiFlash1_5_002
 from langfun.core.llms.vertexai import VertexAIGeminiFlash1_5_0514
 from langfun.core.llms.vertexai import VertexAIGeminiPro1
 from langfun.core.llms.vertexai import VertexAIGeminiPro1Vision
-from langfun.core.llms.vertexai import VertexAIPalm2
-from langfun.core.llms.vertexai import VertexAIPalm2_32K
-from langfun.core.llms.vertexai import VertexAICustom
+from langfun.core.llms.vertexai import VertexAIEndpoint
 
 
 # LLaMA C++ models.