Fix Sagemaker Endpoint documentation (#13660)

- **Description:** fixed the transform_input method in the example., 
  - **Issue:** example didn't work,
  - **Dependencies:** None,
  - **Tag maintainer:** @baskaryan,
  - **Twitter handle:** @Ravidhu87

docs/docs/integrations/llms/sagemaker.ipynb

@@ -141,7 +141,7 @@
     "    accepts = \"application/json\"\n",
     "\n",
     "    def transform_input(self, prompt: str, model_kwargs: Dict) -> bytes:\n",
-    "        input_str = json.dumps({prompt: prompt, **model_kwargs})\n",
+    "        input_str = json.dumps({\"inputs\": prompt, \"parameters\": model_kwargs})\n",
     "        return input_str.encode(\"utf-8\")\n",
     "\n",
     "    def transform_output(self, output: bytes) -> str:\n",
@@ -197,7 +197,7 @@
     "    accepts = \"application/json\"\n",
     "\n",
     "    def transform_input(self, prompt: str, model_kwargs: Dict) -> bytes:\n",
-    "        input_str = json.dumps({prompt: prompt, **model_kwargs})\n",
+    "        input_str = json.dumps({\"inputs\": prompt, \"parameters\": model_kwargs})\n",
     "        return input_str.encode(\"utf-8\")\n",
     "\n",
     "    def transform_output(self, output: bytes) -> str:\n",