[WebNN EP] Fix bug in interpreting ONNX's pads into WebNN's padding (#17325)
The ONNX's pads is [beginning_height, beginning_width, ending_height,
ending_width], while WebNN's padding is [beginning_height,
ending_height, beginning_width, ending_width]. We should permute the
ONNX's pads to [0, 2, 1, 3] for WebNN.