[Pandora] - update libavatar to pandora gob state

* Delete libavatar experimental
* Modify Android.bp to take libavatar from external into account
* Add new example.py to match the pandora_gob one
* Delete connect.py (superset by example.py)

Test: m avatar_runner & avatar_runner example.py
config_bumble_vs_bumble.yml -v
Bug: 260774624

Change-Id: I2fb4a370a8619ec09e5933399881c445e4960483