Remove the dragged tile when existing the current tiles grid

The removal zone would received the "onEntered" callback when the drag
is started, regardless of position. As a result the tile was removed for
a frame. Moving this to the "onExited" callback from the tiles grid
fixes this

Also cleans up the unsused `EditTileListState#updateLargeWidth` method

Test: manually
Flag: com.android.systemui.qs_ui_refactor_compose_fragment
Fixes: 406684456
Fixes: 406418313
Change-Id: I1bd2e72e9dda9843b9f51468d04694e100e886f9