Fix ComponentCreator to Avoid Wrapping Children in Array for React.createElement

[frano-m]

In ComponentCreator, children are currently passed to React.createElement wrapped in an array.

This results in components receiving [null] or [child] instead of null or child.

Some components are not expecting children, i.e. MuiChip and a warning is issued for example: Failed prop type: The prop children is not supported. Please remove it.