Implement brightness slider unfurl in QQS->QS translation according to spec.

The main issue was that the brightness slider needed to have a set of different translations applied, with incompatible interpolators. This change simplifies the implementation to avoid the need for these different translations, ultimately solving the root cause of the issue.

Some background on this change:
- the mTranslateWhileExpanding is not used anymore - it was only set to true in split-shade mode, but then the expansion progress is always (hardcoded to 1) [http://cs/android-internal/frameworks/base/packages/SystemUI/src/com/android/systemui/shade/NotificationPanelViewController.java;l=2438-2441;rcl=21c205b93846470b2c4786361fe59e404a95ed6a], thus the animator never produces a translationY != 0. Thus removed it.
- The mQSTileLayoutTranslatorAnimator is undoing the motion applied in [QSFragment](http://cs/android/frameworks/base/packages/SystemUI/src/com/android/systemui/qs/QSFragment.java;l=658;rcl=bbf0913e49af9615a0d9bf84835fe1725812f78e). The exception to this is the expanded-shade-edge-swipe-down on lock-screen, where QSAnimator would not compensate, since the animator gets [pinned to 1](http://cs/android/frameworks/base/packages/SystemUI/src/com/android/systemui/qs/QSAnimator.java;l=654;rcl=bbf0913e49af9615a0d9bf84835fe1725812f78e). Now, just applying the motion in this case. This eliminates the implicit dependency between the two places, AND more importantly, removes the need to compensate for the motion with a linear interpolator.

Bug: 203537805
Bug: 243261680
Test: Manual on phone and tablet (split shade)

Change-Id: I85cef48fc9e695d32e67fa35b2a49f01c10b5293