langchain: fix deprecation decorators on extraction chains (#21276)

Calling any of these raises
```
ValueError: A pending deprecation cannot have a scheduled removal
```

libs/langchain/langchain/chains/openai_functions/extraction.py

@@ -59,7 +59,6 @@ Passage:
         "https://github.com/langchain-ai/langchain/discussions/18154"
     ),
     removal="0.3.0",
-    pending=True,
     alternative=(
         """
             from langchain_core.pydantic_v1 import BaseModel, Field
@@ -130,7 +129,6 @@ def create_extraction_chain(
         "https://github.com/langchain-ai/langchain/discussions/18154"
     ),
     removal="0.3.0",
-    pending=True,
     alternative=(
         """
             from langchain_core.pydantic_v1 import BaseModel, Field

libs/langchain/langchain/chains/openai_tools/extraction.py

@@ -30,7 +30,6 @@ If a property is not present and is not required in the function parameters, do
         "https://github.com/langchain-ai/langchain/discussions/18154"
     ),
     removal="0.3.0",
-    pending=True,
     alternative=(
         """
             from langchain_core.pydantic_v1 import BaseModel, Field

libs/langchain/langchain/chains/structured_output/base.py

@@ -41,7 +41,6 @@ from langchain_core.utils.function_calling import (
         "https://github.com/langchain-ai/langchain/discussions/18154"
     ),
     removal="0.3.0",
-    pending=True,
     alternative=(
         """
             from langchain_core.pydantic_v1 import BaseModel, Field
@@ -160,7 +159,6 @@ def create_openai_fn_runnable(
         "https://github.com/langchain-ai/langchain/discussions/18154"
     ),
     removal="0.3.0",
-    pending=True,
     alternative=(
         """
             from langchain_core.pydantic_v1 import BaseModel, Field