Form Form-Item prop 'error' is not passing input's error message

### Description

I am trying to use 'error' prop of Form-Item to show custom validation message for one of my form inputs but form.state.error is still empty string.

### Solution

Pass error message from 'error' prop to input state.

### Additional Information

Information about 'error' prop was found on english page (https://eleme.github.io/element-react/#/en-US/form).