🤔 [QUESTION] Is it possible to set a different color scheme for a single bar of Bullet chart?

### 🐛 Question description

Hi! I need to set a different color scheme for a single bar of Grouped Bullet plot. How can I do that?
Thank you!

### 💻 Link to minimal reproduction

[g2plot](https://g2plot.antv.antgroup.com/en/examples/progress-plots/bullet/#grouped)

[codesandbox](https://codesandbox.io/api/v1/sandboxes/define)

### 🏞 Expected result


### 🚑 Any additional [like screenshots]

* **G2Plot Version**: last
* **Platform**: react

Start with the linked G2Plot grouped bullet example and inspect the chart configuration used there. Determine whether a single bar can receive a distinct color scheme, and define the relevant configuration or limitation clearly; the issue is done when the requested behavior is supported or its usage is documented.

Written by the indexing model from the issue text.