add missing type: ignore

Author: AntoineSimoulin

torchvision/transforms/v2/functional/_type_conversion.py

@@ -8,7 +8,7 @@
 from torchvision.utils import _log_api_usage_once
 
 if TYPE_CHECKING:
-    import nvcv
+    import nvcv  # type: ignore[import-not-found]
 
 
 @torch.jit.unused