langchain[patch]: Cerebrium model_api_request deprecation (#12704)

- **Description:** As part of my conversation with Cerebrium team,
`model_api_request` will be no longer available in cerebrium lib so it
needs to be replaced.
  - **Issue:** #12705 12705,
  - **Dependencies:** Cerebrium team (agreed)
  - **Tag maintainer:** @eyurtsev 
  - **Twitter handle:** No official Twitter account sorry :D

---------

Co-authored-by: Bagatur <baskaryan@gmail.com>

libs/langchain/langchain/llms/cerebriumai.py

@@ -1,6 +1,7 @@
 import logging
 from typing import Any, Dict, List, Mapping, Optional
 
+import requests
 from langchain_core.pydantic_v1 import Extra, Field, root_validator
 
 from langchain.callbacks.manager import CallbackManagerForLLMRun
@@ -89,24 +90,21 @@ class CerebriumAI(LLM):
         run_manager: Optional[CallbackManagerForLLMRun] = None,
         **kwargs: Any,
     ) -> str:
-        """Call to CerebriumAI endpoint."""
-        try:
-            from cerebrium import model_api_request
-        except ImportError:
-            raise ValueError(
-                "Could not import cerebrium python package. "
-                "Please install it with `pip install cerebrium`."
-            )
-
+        headers: Dict = {
+            "Authorization": self.cerebriumai_api_key,
+            "Content-Type": "application/json",
+        }
         params = self.model_kwargs or {}
-        response = model_api_request(
-            self.endpoint_url,
-            {"prompt": prompt, **params, **kwargs},
-            self.cerebriumai_api_key,
-        )
-        text = response["data"]["result"]
-        if stop is not None:
-            # I believe this is required since the stop tokens
-            # are not enforced by the model parameters
-            text = enforce_stop_tokens(text, stop)
-        return text
+        payload = {"prompt": prompt, **params, **kwargs}
+        response = requests.post(self.endpoint_url, json=payload, headers=headers)
+        if response.status_code == 200:
+            data = response.json()
+            text = data["result"]
+            if stop is not None:
+                # I believe this is required since the stop tokens
+                # are not enforced by the model parameters
+                text = enforce_stop_tokens(text, stop)
+            return text
+        else:
+            response.raise_for_status()
+        return ""