ADMIN WEB - Catch nulls in json body

When we want to create a row with a non-required field, if we click/select the non-required field and do not type anything, it will send a null to the backend like this:
```json
{
  "name": "Keppo",
  "last_name": null,
  "email": "hello@wiringbits.net",
  "password": "asd"
}
```