Settings: SlimPie give user ability to reduce trigger heights if IME keyboard shows (2/2)

Add a user option to reduce left and right trigger of SlimPie if keyboard shows up
(especially usefull for swipe keyboard which most keyboards are nowadays). Enabled
by default user can disable it in settings

PS:
- fix category string

Change-Id: Ia5ae621a5e63b2efd10180cfbe1876b14a63c866