Removed strong zoom as shade starts to be pulled

Removed steep animation curve when the shade is being pulled, such as
it's not closer to what exists in other system areas, like all apps
drawer and -1.

It was necessary to convert ints to floats, given that conversion was
causing precision loss, making the wallpaper zoom stutter.

Test: pull down drawer over app or launcher
Test: launch apps from QS
Test: change device brightness from QS
Test: atest NotificationShadeDepthControllerTest
Fixes: 195667456
Change-Id: Ibe778fbe3811434dd5123a471eec0d21db1fd09a