perf: single yield per line in stream chunks handler (open-webui#23266)

Author: Algorithm5838

backend/open_webui/utils/misc.py

@@ -961,18 +961,15 @@ async def yield_safe_stream_chunks():
                         skip_mode = False
                         yield line
                     else:
-                        yield b'data: {}'
-                        yield b'\n'
+                        yield b'data: {}\n'
                 else:
                     # Normal mode: check if line exceeds limit
                     if len(line) > max_buffer_size:
                         skip_mode = True
-                        yield b'data: {}'
-                        yield b'\n'
+                        yield b'data: {}\n'
                         log.info(f'Skip mode triggered, line size: {len(line)}')
                     else:
-                        yield line
-                        yield b'\n'
+                        yield line + b'\n'
 
             # Save the last incomplete fragment
             buffer = lines[-1]
@@ -986,7 +983,6 @@ async def yield_safe_stream_chunks():
 
         # Process remaining buffer data
         if buffer and not skip_mode:
-            yield buffer
-            yield b'\n'
+            yield buffer + b'\n'
 
     return yield_safe_stream_chunks()