Interact form always send boolean field with false value

[judgerain]

Checklist

• I have verified that that issue exists against the master branch of Django REST framework.
• [x ] I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to the discussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to be in the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

In the Built-in API documentation, while using the "Interact" forms, boolean field always use false value in request.

Expected behavior

It should send value depending from checkbox state.

Actual behavior

[levidyrek]

I will take this one.