Do you have a workbook? Or an image?
I'm not sure if there's a way to change the default palette for every single dimension and measure all at once.
However, you can set the default color palette for a specific dimension or measure,
Right-Click your dimension, 'Project Choice Rating'.
Select Default Properties >> Color
Select the color palette from the dropdown menu
Click assign palette.
You should be good for that specific dimension.
However, you would have to go through that process for each dimension if you want all of them to have this new default color palette.
I could be wrong, but I'm not sure there's a way to do this in Tableau, unfortunately.