Controlled Select with a nullable value

[fuma-nama]

I want to keep the select component to be controlled even with a null value.

The Select component doesn't allow a null value, only string or undefined (uncontrolled) are accepted.

For example, I expect that if the value is null (not undefined), it should display the placeholder.
However, it causes unexpected behavior and the placeholder doesn't even appears.

How can I achieve that, or are there some alternatives?

[benoitgrelard]

Related to #1569