Prevent unnecessary animation when dragging window within same display

The commit addresses an issue in MultiDisplayVeiledResizeTaskPositioner
where dragging a window within the same display could trigger an
unnecessary animation due to minor changes in width or height caused by
DPI scaling.

The fix involves checking if the drag operation occurs within the same
display. If it does, the logic falls back to the single-display drag
behavior, where we only updates the window left and top coordinates.

See details in b/390370556#comment2

Bug: 390370556
Test: Manual
Flag: com.android.window.flags.enable_connected_displays_window_drag
Change-Id: I6797e115361577955443ae0492c1b72dd1519de1