Added required changes to use DropTargetManager in Launcher.

Updated DragZoneFactory to provide bubble bar drop zone Rect. Do not
remove secondDropTargetView from parent container if there is no drop
zone.

Bug: 411506181
Flag: com.android.wm.shell.enable_create_any_bubble
Test: Manual. Go to overview screen and drag app icons from the taskbar
over the bubble bar

Change-Id: Ib2791ac16dbc91fd8372d726b896ac0ba2bf9e64