More sanity checks on Open API Builder

[DiegoPino]

What?

See #394 also

On live/production test @alliomeria detected a few issues with Form Validation (enumerations and UUID Entity validation) + Controller output (on empty we don't return a Response at all)

Will open a pull in a while to keep refining this new tool

[alliomeria]

Thank you @DiegoPino, for safely catching 🐛 and releasing 🦋.

I will keep testing and checking in production and let you know if I come across any other potential issues.

[DiegoPino]

Resolved for now via 1d8963d
More code/issues will keep popping up. But fixes need to go in. Thanks