When changing data, keep customized color scheme choice

[boogheta]

When regenerating the same viz over and over with different datasets, one can already use the "Change data" button to keep most of the viz settings identical which is really convenient. Although, the color scheme choice remains the same but not its options. For instance if one chooses a Sequential color scale, chooses the blue one then adjusts the color choice for the start value, it needs to be reset every time the data is changed.