Drop the cloned windows from visible window list

Currently the cloned windows is avaialbe from window list,
however the node info from the cloned window is incorrect.
To avoid confusion, we would drop them for a short term solution.

Bug: 230300971
Test: manually test with switchaccess
      adb shell dumpsys accessibility to observe the window list
Change-Id: I7a03376567698a493c9eb5e26d1f3390aacdb408