[fix] Revert "fixing mm placeholder replacement issue with gemma3" (#28285)

Signed-off-by: Kevin H. Luu <khluu000@gmail.com>

vllm/model_executor/models/gemma3_mm.py

@@ -401,7 +401,7 @@ class Gemma3MultiModalProcessor(BaseMultiModalProcessor[Gemma3ProcessingInfo]):
 
         def get_repl_toks(tok: int) -> list[int]:
             if tok == newline_3:
-                return [newline_2, newline_1]
+                return [newline_1, newline_2]
             if tok == newline_4:
                 return [newline_2, newline_2]