Properly handle MultiObjectiveSettings #863
Description
Raised in #857
Since #805 both options --io:propsasmulti and --multiobjective:lex could eventually be abolished since we now have first-class support of multi-objective and lexicographic properties in PRISM- and JANI-style specifications.
The workaround in #857 also still fails if a user sets --propsasmulti.