array io save fails on non-sorted extra dims

[Manangka]

In GitLab by @Huite on Feb 7, 2021, 19:42

Calling e.g. imod.idf.save results in an error if a time dimension isn't sorted.

The resulting error (mentioning "idf", which is the "extra dim"), is confusing.

Could either be a thing with the stack function, or add a better error message.