[BUG] Interface signature is missing options "undefined" and "null" present in signature of implemting class

[JasonMarxTNG]

Description

In commit 3756c3b merged in version v7.3.0 additional options "undefined" and "null" are implemented, but the interface is not changed accordingly, see comment 3756c3b#r138524981.

openapi-generator version

v7.3.0

Suggest a fix

Change interface signature accordingly.