Add Animation Support for go.Sankey Plots Similar to go.Scatter and go.Bar

Description

I would like to request the addition of animation support for go.Sankey plots, similar to the functionality available in go.Scatter and go.Bar.

Expected Outcome

The go.Sankey plot should have a parameter in the layout for animations, similar to the updatemenus feature. An example of the desired configuration is shown below:

"updatemenus": [{
    "type": "buttons",
    "buttons": [{
        "label": "Your Label",
        "method": "animate",
        "args": [/* Animation arguments here */]
    }]
}]

This feature would allow users to add animations to go.Sankey plots, enhancing their interactivity and visual appeal.

首先比较 go.Scatter 和 go.Bar 现有的动画支持与 go.Sankey 入口点，重点关注 layout updatemenus 和 animate 方法是如何暴露的。完成的标准是 go.Sankey 接受等效的动画配置，并且回归测试或示例演示所请求的按钮和动画参数。