Fix a bug in properties support module, revealed after work on [#50074251]

A tiny typo - ".descriptor" was missing. It was revealed when one
commit from [#50074251] removed all manual calls of engine setters.
Only propertiesSupport.setRawValues call was left, so the engine
properties were never updated.
Create elements before setting main properties

[#50074251]

Sounds strange, but the reason is that "polarAAEpsilon" option sets
properties of existing elements. So, without this change (and after
other, recent changes related to engine setters), the engine setup was
failing. Probably this can be simplified during future work on
elements refactoring.