EZP-22098 fixed rest api bug when a user creat a content type with 0 as min or max value for a float or integer

In the REST API, if you set 0 as the maximum or the minimum allowed value on a Float or Integer field definition, the validatorConfiguration will contain false instead of 0.

[x] Fixed the problem, the validatorConfiguration return 0 instead of FALSE
[ ] unit tests

https://jira.ez.no/browse/EZP-22098?jql=labels%20%3D%20rfs