[sf-newfe] Fix snapshot paths for recursive mirror paths

If we are mirroring a hierarchy that already contains a mirror
then we need to track all the mirror roots inorder to have
a unique path.

Test: presubmit
Test: can screenrecord magnifier
Test: dumpsys SurfaceFlinger --frontend
Bug: 238781169
Change-Id: Id2272981f6f6244f41328428b73184bccf5d1888