Add support for SHACL patterns in the Wizard API

Hi!

I've noticed that the current XFSC SD Creation Wizard does not support regex patterns in the SHACL shapes (sh:pattern) out of the box. However, it seems like the frontend part of the wizard is already prepared for this functionality as it supports patterns in the validators. I quickly glimpsed over the API code and added these few lines which seems to do the trick. If there was any reason why this was not already added or why this should not be done this way, please let me know, but at least for our use cases in the POSSIBLE project this seems to work perfectly fine so far 😄