Input's fluid property no effect when it is in a Form.Field?

## Bug Report

### Steps
I put an Input in the Form.Field, but seems the `fluid` is not effected?

### Expected Result
The Input should take the full width of the container in Form.Field in a Form.

### Actual Result
The Input width is short.

### Version
0.44

### Testcase
[Fork, update, and replace this sandbox to show the bug]:

