Clear indicator surfaces on drag end for same-display drags

Using DragPositioningCallbackUtility for same-display drag bounds
(I6797e11536) prevented the MultiDisplayDragMoveIndicatorController from
properly clearing indicator surfaces on drag end. This caused potential
surface leaks when drags started and ended on the same display but
traversed other displays.

This change ensures that onDragEnd() is always called on the indicator
controller, guaranteeing that all surfaces are properly disposed of.

Bug: 401464337
Test: Manual; atest
Flag: com.android.window.flags.enable_connected_displays_window_drag
Change-Id: Iebfc4d1b017be695d6d5bbb8ef61670c276eefe9