OnePager populates response curves only in Gray for all spendings

robyn version: `0.3.6`
python version: `3.11.1`

I am using robynpy==0.3.6 in python edition. My python version is 3.11. I am following the [tutorial1_src](https://github.com/facebookexperimental/Robyn/blob/main/python/src/robyn/tutorials/tutorial1_src.ipynb) to build my MMM with my data where I am using several different parameters but the skelaton is same with the tutorial.

my problem is at the response curves all of the variables' colors is the same and gray. So, I can't distinguish them.

Here is the screen shot: