Move onChangeThreadType out from inner class component to outer "Connected" functional component.

As part of the work to refactor ThreadSettingsModal... specifically to turn it into a functional component.

Depends on D3767

1. Open ThreadSettingsModal
2. Change the thread type
3. Log values in onChangeThreadtype to ensure that they continue to be as expected
4. Hit save after changing the color and ensure that the thread description changed as expected