Add ToggleButton accessibility role

[rectified95]

react/react-native@da899c0 added the ToggleButton role for Android - do we want to bring this to RNW? Currently we do this:

case winrt::Microsoft::ReactNative::AccessibilityRoles::Switch: // Both ToggleSwitch and ToggleButton return "Button"
    return winrt::AutomationControlType::Button;                                                    

vnext/Microsoft.ReactNative/Views/DynamicAutomationPeer.cpp#L52