Do not redraw if no change on reparent

An example is when transferring a starting window in a task with
embedded activities. The configuration of the starting window
will be overridden by task, so there won't be configuration change
when transferring the window between activities. And if the window
was drawn, it is unnecessary to request redraw by onSyncReparent
-> WindowState#prepareSync() -> requestRedrawForSync().

Though this can avoid potential SurfaceSyncGroup timeout indirectly,
this is still a reasonable performance optimization.

Bug: 279798720
Test: atest SyncEngineTests#testReparentIn
Change-Id: Iebfb662b579eceecc470719fa6a2dc8ba8df332f