Add comma between args

Author: dyastremsky

src/c++/perf_analyzer/genai-perf/genai_perf/wrapper.py

@@ -57,7 +57,8 @@ def build_cmd(args, extra_args):
             "input_format",
             "model",
             "backend",
-            "extra_inputs" "output_format",
+            "extra_inputs",
+            "output_format",
             # The 'streaming' passed in to this script is to determine if the
             # LLM response should be streaming. That is different than the
             # 'streaming' that PA takes, which means something else (and is