Use slider label in dropdown instead of manual label

[casieber]

The fabric Slider component supports a label prop that will render a label for the slider, but when I tried to use that in the Settings dropdown, the label gets poorly positioned and cut off.

To work around that issue I simply stopped using the label prop and manually render extra subMenuProps items that simply display the title for the next item and preventDefault on any click event on them.

This works okay visually, but these label-only items do still appear clickable and force me to split up the label from the actual slider.

We should investigate if there is a way to use the slider component with its label prop inside of the menu.