groupClade behaves differently for evonet and treedata objects

[arthurKocher]

The unspecified lineages are marked as "Undefined" in the first case and NA in the second.

Maybe accord and or add an option to specify what value unspecified lineages should take? This is quite minor issue though so do not spend to much time on this if too complicated.

test code

#evonet object
retnet = read.enewick("../data/retnet.nwk")
ggret(groupClade(data = retnet, nodes = c("A", "B"), "AB clade"), aes(color=clade))
#treedata object
net3=ggarg::read.beast("../data/retnet.nexus")
ggret(groupClade(data = retnet3, nodes = c("A", "D"), "AB clade"), aes(color=clade))

[arthurKocher]

works