Ignore name-defined mypy error for _csv._writer

Author: lochhh

movement/io/save_bboxes.py

@@ -436,7 +436,7 @@ def _write_via_tracks_csv(
 
 
 def _write_single_row(
-    writer: "_csv._writer",  # requires a string literal type annotation
+    writer: "_csv._writer",  # type: ignore[name-defined]
     xy_values: np.ndarray,
     wh_values: np.ndarray,
     confidence: float | None,