Add API to topshim adapter facade to toggle discovery state of the current topshim device.

Added appropriate testing for the same.

Bug: 261616658
Test: mma -j $(nproc)
Test: ./build.py
Test: system/gd/cert/run --clean --topshim
Tag: #floss
Change-Id: I0bdf54175dec3303a48b6a9b6fa8650bbbe6f870