Fix conversion of missing attributes (due to being optional?) and handling depth32/cv::Mat data

Using the aron types of https://git.h2t.iar.kit.edu/sw/playground/demo-mp-library/-/tree/test-vmp-memory/source/demo_mp_library/armem_movement_primitive/aron and https://git.h2t.iar.kit.edu/sw/armarx/skills/programming-by-demonstration/-/tree/dev/source/programming_by_demonstration/record_demonstration/aron, these fixes were required to convert the received ice data into dtos.

Especially the conversion of the depth32 data looks strange and should be checked by someone who is more familiar with the types underlying Aron at this point. @plewnia, could you please have a look, and/or do you have a suggestion on who else might be knowledgeable in these aspects?