chore: import upstream snapshot with attribution

tests/langchain/sample_code/model_with_config.py

@@ -0,0 +1,18 @@
+from langchain_core.prompts import PromptTemplate
+from langchain_core.runnables import ConfigurableField
+from langchain_openai import ChatOpenAI
+
+from mlflow.models import set_model
+
+model = ChatOpenAI(temperature=0).configurable_fields(
+    temperature=ConfigurableField(
+        id="temperature",
+        name="LLM temperature",
+        description="The temperature of the LLM",
+    )
+)
+
+prompt = PromptTemplate.from_template("Pick a random number above {x}")
+chain = prompt | model
+
+set_model(chain)