fix a typo

Author: mohammedahmed18

codeflash/result/create_pr.py

@@ -281,8 +281,8 @@ def check_create_pr(
     function_trace_id: str,
     coverage_message: str,
     replay_tests: str,
-    concolic_tests: str,
     root_dir: Path,
+    concolic_tests: str = "",
     git_remote: Optional[str] = None,
     optimization_review: str = "",
     original_line_profiler: str | None = None,