Unnecessary eval prevents execution in CSP environment

The script uses the command `eval` in line [1242](https://github.com/brutusin/json-forms/blob/d0fa10a7c364134c9e81911dd60a9e1f80d47385/dist/js/brutusin-json-forms.js#L1242). As far as I can see, this command is useless, as there are no other variables that require this function.

However, usage of the `eval` command collides with Content-Security-Policies. Those usually deny this command and will block of the data insertation. Allowing this command will allow it everywhere and contradicts the purpose of CSP.

Minor changes in the following PR will remove this command and allows it to run successfully in a CSP controlled environment.