The decoding did not unwrap the extension objects that the
structures are wrapped into when encoded if the variant contains an
array of structures.

The implemented unit tests of this PR reveals the issue. Also the
test parseCustomArray is updated to what we belive is the correct
behavior.

We have a solution implemented that passes all unit tests but needs
to be clean up before published. We publish the unit tests to notify
about the issue until the solution is ready.

Co-authored-by: Julius Pfrommer <julius.pfrommer@web.de>