Fix pyrefly version (#1456)

Author: evroon

backend/pyproject.toml

@@ -55,7 +55,7 @@ dev = [
     "mypy==1.19.0",
     "pluggy==1.6.0",
     "pylint==4.0.2",
-    "pyrefly>=0.41.3",
+    "pyrefly==0.41.3",
     "pytest-asyncio==1.3.0",
     "pytest-cov==7.0.0",
     "pytest-xdist==3.8.0",