Using a weighted average for direction estimation

This gives a higher weight to the most recent translations in the
internal translation buffer used to estimate the detaching direction. It
mitigates cases in which the esimtation is wrong after a sudden and
large translation opposite to the real detach direction.

Test: manual. Verified the dismiss direction is the same as the detach
  direction after sudden translations in the opposite direction.
Flag: com.android.systemui.magnetic_notification_swipes
Bug: 414432406

Change-Id: I381d40966cb6c1f280c3acfa069151e1fb596524