Dendrogram not reordering cell types in plot

[Al-Murphy]

1. Bug description

When ewce_plot() is run with make_dendro = TRUE, the resulting column order in the $withDendro output plot is the same as the plain plot meaning there is no update to the cell type orders based on the dendrogram. It is unclear if this has always been the case or is a bug introduced by the refactoring.

Adding a fix and a unit test for this now and will push to both the release and dev branch.

[Al-Murphy]

The issue only affected cases where there was no plotting values in the ctd i.e. no value in ctd[[annot_level]]$plotting.

Fix implemented in v1.11.1 and release v1.10.1