[Feature] 希望桑基图（sankey）支持滚动条以及缩略轴

[LofiSu]

What problem does this feature solve?

增强桑基图功能和完善性，让sankey支持滚动条以及缩略轴

What does the proposed API look like?

散点图api示例：https://echarts.apache.org/examples/zh/editor.html?c=custom-error-scatter
热力图api示例：https://echarts.apache.org/examples/zh/editor.html?c=area-simple

[Ovilia]

These two examples use dataZoom, which is designed to scale with axes. But sankey don't have such axes that can use dataZoom. A possible solution would be supporting zooming with roam: true as a new feature and add thumbnail (ralated to #17471) to it. This can be a large feature and let's see what we can do in ECharts 6.

[dberardo-com]

IMO sankey diagrams should support drop-offs. AFAIK the only library supporting dropoff is a commercial one: https://docs.anychart.com/Basic_Charts/Sankey_Diagram#dropoffs so adding dropoffs would be a strong diversifying factor for echarts when compared to non-commercial libraries out there.