Fix: adjust IDs and size of Genre objects for testing

[eric-pSAP]

Changed ID values of Genre objects to UUIDs and decreased depth of the POSTed Genre object to match the maximum depth of DELETE.

[cla-assistant]

All committers have signed the CLA.

[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}