community[patch]: callback before yield for cloudflare (#26927)

**Description:** Moves yield to after callback for `_stream` function
for the cloudfare workersai model in the community llm package
**Issue:** #16913

libs/community/langchain_community/llms/cloudflare_workersai.py

@@ -105,9 +105,9 @@ def _stream(
                     logger.debug(chunk)
                     raise e
                 if data is not None and "response" in data:
+                    if run_manager:
+                        run_manager.on_llm_new_token(data["response"])
                     yield GenerationChunk(text=data["response"])
-                if run_manager:
-                    run_manager.on_llm_new_token(data["response"])
         logger.debug("stream end")
         self.streaming = original_steaming