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.

首先运行提供的 Python 最小示例，使用 plotly.graph_objects.Surface 并启用 contours_z，将等高线颜色与曲面 colorscale 进行比较。跟踪 Surface 的等高线着色路径，并验证等高线是否使用完整的所选 colorscale；当等高线与对应的曲面颜色匹配时即表示完成。