experimental[patch]: prompts import fix (#20534)

Replaced `from langchain.prompts` with `from langchain_core.prompts`
where it is appropriate.
Most of the changes go to `langchain_experimental`
Similar to #20348

libs/experimental/langchain_experimental/autonomous_agents/autogpt/prompt.py

@@ -1,11 +1,11 @@
 import time
 from typing import Any, Callable, List, cast
 
-from langchain.prompts.chat import (
-    BaseChatPromptTemplate,
-)
 from langchain.tools.base import BaseTool
 from langchain_core.messages import BaseMessage, HumanMessage, SystemMessage
+from langchain_core.prompts.chat import (
+    BaseChatPromptTemplate,
+)
 from langchain_core.vectorstores import VectorStoreRetriever
 
 from langchain_experimental.autonomous_agents.autogpt.prompt_generator import get_prompt