Do not set 2D contour plot grid if grid is False in analytic_triangle_plot
In _analytic_triangle_plot
if grid
is set to False you get the error:
/home/matt/miniconda3/envs/cwinpy/lib/python3.8/site-packages/pesummary/core/plots/publication.py:472: UserWarning: First parameter to grid() is false, but line properties are supplied. The grid will be enabled.
ax3.grid(grid, zorder=10)
and the grid still gets plotted on the 2d contour plot due to the zorder
argument being present. This MR fixes this by placing the ax3.grid()
call in an if statement.