Tweak NotifcationManagerService

-Add mWasScreenOn boolean to check if screen is on, and then if the user
is in the color picker for cutom led force update to preview selected
led color with chosen lengh & speed.

Change-Id: Ic9e1b67f9e8e50f21495555ef9f253bf68713e7b
Signed-off-by: cj360 <ayunker551@gmail.com>