Add `grid` argument to `plot_pattern()` to avoid overplotting

[hanneoberman]

Hide geom_tile borders for datasets with many columns (or missing data patterns, not shown).

ggmice::plot_pattern(data.frame(rbind(rep(NA, 500), 1:500)))

^{Created on 2023-12-07 with reprex v2.0.2}

[hanneoberman]

And also plot_pred and plot_corr

[hanneoberman]

See code for plot_miss