onnxruntime

[WebNN EP] ConvTranspose should calculate the pads or output shape (#21292)

This PR adds the missing pads and output shape calculation for
ConvTranspose.

Per ONNX spec:
- If the output shape is explicitly provided, compute the pads.
- Otherwise compute the output shape, as well as the pads if the
auto_pad attribute is SAME_UPPER/SAME_LOWER.