Fix transition for non-wallpaper activity.

for task_close_enter / task_close_exit activity animation,
the default set showWallpaper as true,
so WallpaperController find wallpaper target will set
non-wallpaper activity as wallpaper target according
Animation.getShowWallpaper().

the case can see when tap an non-wallpaper activity start
another non-wallpaper activity, before transition finish then
press back quickly will found the animation will changed,

It result the transition type will be TRANSIT_WALLPAPER_CLOSE
rather then TRANSIT_TASK_CLOSE when 2 non-wallpaper activities
launch / finish case.

since we don't want to change the transition for this case,
check if wallpaper target has FLAG_SHOW_WALLPAPER, if don't,
won't need to change the transition type.

Bug: 75261877
Test: atest ActivityManagerTransitionSelectionTests
Change-Id: Ibbe09e9194b474d1221359ecc7dc62d9fbd5f462