MouseEvent.mozInputSource is deprecated. Use PointerEvent.pointerType instead.

As the source code indicates here, adobe/react-spectrum has updated its event handler from which this code was lifted to:

https://github.com/adobe/react-spectrum/blob/70ee05233f66cbeb1772b1aa8a24a8026f134a4b/packages/react-aria/src/utils/isVirtualEvent.ts#L26-L40