floss: Refactor btstack initialization order (2/4 BluetoothAdmin)

This patch does:
- Move the toggle_enabled_profiles functionality from Bluetooth to
  BluetoothAdmin. The reason is that the function makes BluetoothMedia
  a deep dependency of Bluetooth.
- BluetoothAdmin now depends on Bluetooth, BluetoothMedia, and
  SocketManager. It is initialized after adapter is ready and directly
  invokes handle_admin_policy_changed when policy is init-ed/changed.
- BluetoothAdmin now listens to Bluetooth's device events through the
  callback system.

Some backgrounds:
  We want to get rid of the redundant `Option` of the topshim objects
  that is causing many verbosities and confusing snippets (We all know
  we can't do anything without the objects... Then why is it optional?).
  The overall direction is to remove all Bluetooth's dependencies on
  initialization, because the Bluetooth topshim object needs to be
  initialized first before all other topshim objects can be obtained.

Bug: 254870880
Tag: #floss
Test: mmm packages/modules/Bluetooth
Test: bluetooth_AdapterEPHealth.all_floss
Flag: EXEMPT, Floss-only changes
Change-Id: Ib0871d738675f1370cc6469106fa7f087a296557