Bad error messages when default via padstack is not set

[alex-fu27]

If there is a default via rule, but the padstack is set to (None) (which is the case if the via rule was newly created, then placing a via with the "place via" tool will throw this error:

Seq	Level	Domain	Message; Detail
11	Warning	Tool	Didn't find a via for net VCC; make sure that there's a default via rule

Which is okay, at least it points the user at the via rules, but adding a via while routing a track will cause

Seq	Level	Domain	Message; Detail
8	Critical	Core	exception thrown in tool_update; Padstack 00000000-0000-0000-0000-000000000000 not found

which is not very descriptive.

(in Horizon 2.4.0)