Color of Contour lines in Surfaces with colormap are not correctly set

I think there is an issue in the way the lines plot by a contours in a Surface object when selecting the color.
I think the color is not being correctly selected by each of the lines. They are supposed to follow the colorscale, but they just follows half of it.

Here there is a minimum example of code to simulate the error:

import numpy as np
import plotly.graph_objects as go

x = np.linspace(0, 1, 100)
y = np.linspace(0, 1, 100)
x_grid, y_grid = np.meshgrid(x, y)

z = x_grid + y_grid

params = {
    'colorscale': 'rainbow',
    'surfacecolor': z,
    'showscale': True,
    'colorbar': {
        'title': 'z',
    },
    'contours_z': {
        'show': True,
        'usecolormap': True,
        "project_z": True,
    }
}

trace = go.Surface(
    x=x,
    y=y,
    z=z,
    **params)

fig = go.Figure(data=[trace])
fig.write_image("test.png")
fig.show()

In the example, the expected behavior will be for the contour lines to be the same color as the surface, but they are not.

Start by running the provided Python minimum example with plotly.graph_objects.Surface and contours_z enabled, comparing the contour colors with the surface colorscale. Trace the Surface contour-coloring path and verify that the contour lines use the full selected colorscale; done means the contour lines match the corresponding surface colors.