## What happened?

The **sync** streaming path in `OCIChatConfig.get_sync_custom_stream_wrapper` is missing the `split_chunks` logic that the **async** path (`get_async_custom_stream_wrapper`) already has. When the OCI endpoint batches multiple SSE events into a single HTTP chunk, `chunk_creator` receives a multi-line string and `json.loads()` fails with `JSONDecodeError: Extra data`.

**Expected:** Streaming works the same in sync and async paths.

## Steps to Reproduce

1. Configure litellm to use an OCI model (e.g., `oci/openai.gpt-5.4`) 2. Make a **sync** streaming chat completion call 3. Observe `JSONDecodeError: Extra data` when the endpoint batches multiple SSE events into one chunk

## Relevant log output

``` litellm.APIConnectionError: Extra data: line 3 column 1 (char 123)

File "litellm/litellm_core_utils/streaming_handler.py", line 1611, in __next__ response: Optional[ModelResponseStream] = self.chunk_creator(chunk=chunk)

File "litellm/llms/oci/chat/transformation.py", line 1082, in chunk_creator dict_chunk = json.loads(chunk[5:]) ^^^^^^^^^^^^^^^^^^^^^ json.decoder.JSONDecodeError: Extra data: line 3 column 1 (char 123) ```

## Root Cause

In …