[WebNN EP] Don't covert all inputs except the 0th input for Resize (#18687)
Currently all the inputs of Resize node will be converted to NHWC if the
preferred layout is NHWC, and the ORT will call `IsOpSupportedImpl`
twice, first time the inputs are NCHW, and the second time the inputs
have been converted to NHWC. This would make the validation for scales
input complicated and difficult to identify the height and width values.