fix: set seed for shuffling MMLU samples to allow reproducibility

Author: AarushSah

src/inspect_evals/mmlu/mmlu.py

@@ -200,6 +200,7 @@ def get_mmlu_dataset(
         split=split,
         sample_fields=record_to_sample,
         shuffle=shuffle,
+        seed=42,
     )
 
     # filter dataset if requested