feat: log provider errors to console for better insights (#23379)

* fix: log provider errors that were silently swallowed

* Update main.py

* fix: wrap non-JSON SSE error responses in JSON so middleware handles them

backend/open_webui/main.py

@@ -1797,7 +1797,7 @@ async def chat_completion(
             finally:
                 raise  # re-raise to ensure proper task cancellation handling
         except Exception as e:
-            log.debug(f'Error processing chat payload: {e}')
+            log.error('Error processing chat payload: %s', e)
             if metadata.get('chat_id') and metadata.get('message_id'):
                 # Update the chat message with the error
                 try: