fix: Preprend question tag to rubric critiquing response after editing the predefined prompts to end with <question> to avoid parsing errors

PiperOrigin-RevId: 743653376

Author: vertex-sdk-bot

vertexai/preview/evaluation/utils.py

@@ -593,6 +593,8 @@ def parse_question(txt: str):
 
 def parse_question_blocks(txt: str) -> List[Tuple[str, bool]]:
     """Parses the question blocks from the rubric critique response."""
+    if not txt.startswith("<question>\n"):
+        txt = "<question>\n" + txt
     responses = []
     question_blocks = _QUESTION_BLOCK_REGEX.findall(txt)
     if not question_blocks: