[skip ci] Add comment of deploy mode on benchamrk (#8853)

Signed-off-by: wangting0128 <ting.wang@zilliz.com>

tests/benchmark/milvus_benchmark/metrics/models/metric.py

@@ -34,6 +34,7 @@ class Metric(object):
         self.run_id = int(time.time())
 
     def set_mode(self, mode):
+        # Set the deployment mode of milvus
         self.mode = mode
 
     # including: metric, suite_metric