Extension additions of a SEQUENCE/SET are not set to optional
## Summary
According to the ASN.1 standard, "All fields in extension additions of a SEQUENCE type or a SET type shall be transformed to optional fields". This behavior is missing currently.
Originates from this forum post: https://www.eclipse.org/forums/index.php/t/1112865/
## Titan version
All
## Platform details (OS type and version)
All
/cc @aknappqwt @mmagyari
issue