BHV-12091: regression in moon.ToggleItem due to changes in BHV-5139

### Issue:
moon.ToggleItem subclasses from moon.CheckboxItem. Due to changes in moon.Checkbox and moon.CheckboxItem in BHV-5139 (specifically, using a moon.Icon instead of styling the checkbox directly), toggleItem now shows a checkmark when it shouldn't, and requires other css adjustments
### Fix:
Add an "icon: 'circle'" property to ToggleItem/Switch.js, and modify css to ensure proper color, background-color and position.

Enyo-DCO-1.1-Signed-off-by: Krishna Rangarajan <krishna.rangarajan@lge.com>