Fix contour functions for ssim baselines matlab contour plots

[gilbertogalvis]

This PR fix almost all issues for contour functions tested in https://github.com/plotly/ssim_baselines/tree/main/matlab/contour-plots

NOTE:
To work with contour3 is necessary to set TreatAs Plotly Option parameter to contour3. Example

[X,Y,Z] = sphere(50);
contour3(X,Y,Z);

f = fig2plotly(gcf, 'offline', 0, 'TreatAs', 'contour3'); 

[VolKa79]

Good.
Works for
[X,Y] = meshgrid(-5:0.25:5);
Z = X.^2 + Y.^2;
contour3(Z)

as well as for others cases in
https://www.mathworks.com/help/matlab/ref/contour3.html