chore(developer): handle project version checks cleanly in kmc

Relates to #9948.

While the schema validation does check the version already, it gives a
fairly obtuse message, and we can do better.

Found a secondary issue with a iterator type guard needed in
kpj-file-reader when preparing unit test, which was probably masked in
other tests by not verifying all messages generated, so updated all
infrastructure message tests to verify the full set of messages
generated.