[Lens] Coloring problem on multi metric partition chart

[stratoula]

Kibana version:
8.7

Describe the bug:
This #145948 enabled manual coloring on a partition chart that has more than 1 metric.
If I color one metric with a custom color and then change the function of the other metric, the color is lost.

Steps to reproduce:

1. Create a donut with an average and a median
2. Give to the median a custom color
3. Change the average to last value
4. Check the colors

A similar weird behavior happens when I have 2 metrics with the automatic colors. If I change the function of one the colors swap causing inconsistency among the chart and the dimension panel

Expected behavior:
Colors should not change like that and should be consinstency among the colors depicted on the chart and on the dimension panel.

[elasticmachine]

Pinging @elastic/kibana-visualizations @elastic/kibana-visualizations-external (Team:Visualizations)

[drewdaemon]

Some research:

The crux of the problem seems to be that the palette getCategoricalColor method is called with a different rankAtDepth value in the renderer than it is in the dimension editor/triggers. This seems to occur because the renderer takes the liberty of sorting the dimensions by slice size, whereas the visualization-controlled components are just using the existing dimension order.

In the example in the issue, changing the function to Last value changes the slice order changing that dimensions rankAtDepth from 0 to 1 in the expression renderer.