Hi,

I am trying to generate a Surface plot with color as 4th dimension. In plotly there is an attribute called surfacecolor which manaeges this. But I could not figure out how to do this in holoviews backend plotly. I need something like the following:

```
import plotly.graph_objects as go
import numpy as np
# Data to be plotted
x = np.outer(np.linspace(-2, 2, 30), np.ones(30))
y = x.copy().T
z = np.cos(x ** 2 + y ** 2)
c = np.linspace(5,10,900).reshape(30,30)
# plotting the figure
fig = go.Figure(data=[go.Surface(x=x, y=y, z=z, surfacecolor=c)])
fig.show()
```