Do not add window decor for desks

Window decorations should not be added to desk tasks. Skips the call to
view model for desk tasks.

Bug: 414449402
Flag: com.android.window.flags.enable_no_window_decoration_for_desks
Test: Rotate tablet during drag to desktop
Change-Id: I141c51c6eab8b4f6d1033e323c6db33b9610c2c7