test(sandbox): finalize concurrent apply_patch regression

Author: fscfede-beep

tests/sandbox/test_apply_patch.py

@@ -487,7 +487,7 @@ async def test_apply_patch_serializes_concurrent_operations() -> None:
     original_read = session.read
 
     async def blocking_read(
-        path: Path, *, user: str | None = None
+        path: Path, *, user: object = None
     ) -> io.BytesIO:
         if path == Path("/workspace/source-a.txt") and not entered.is_set():
             entered.set()
@@ -529,4 +529,4 @@ async def blocking_read(
     assert session.files[Path("/workspace/source-a.txt")] == b"a\n"
     assert session.files[Path("/workspace/source-b.txt")] == b"b\n"
     assert session.files[Path("/workspace/target-a.txt")] == b"occupied-a\n"
-    assert session.files[Path("/workspace/target-b.txt")] == b"occupied-b\n"
+    assert session.files[Path("/workspace/target-b.txt")] == b"occupied-b\n"