[Bugfix] Correctly call cudaProfilerStop in benchmarks script (#14183)

Signed-off-by: Brayden Zhong <b8zhong@uwaterloo.ca>

benchmarks/kernels/benchmark_moe.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 import argparse
+import json
 import time
 from contextlib import nullcontext
 from datetime import datetime