Remove setActiveUser together with frameworks/base (see 12/n)

setActiveUser is removed from the @hide API surface and is no longer
necessary. The framework ensures that the correct user is set without
an explicit call, since userId is sent as a parameter to each of the
methods already.

Bug: 157790417
Test: See testing from frameworks/base change (12/n) from the same
      gerrit topic
Change-Id: Id88b818ed0bb1f75f18ac8e9ba7aff2a9b80b319

src/com/android/settings/biometrics/face/FaceSettings.java

@@ -224,7 +224,6 @@ public class FaceSettings extends DashboardFragment {
         if (requestCode == CONFIRM_REQUEST) {
             mConfirmingPassword = false;
             if (resultCode == RESULT_FINISHED || resultCode == RESULT_OK) {
-                mFaceManager.setActiveUser(mUserId);
                 // The pin/pattern/password was set.
                 if (data != null) {
                     mToken = data.getByteArrayExtra(