[Audiosharing] Impl a base controller for audio sharing page.

The preference controllers attached to audio sharing page will extends
this base controller so that their visibility will be updated together
depending on the main switch state.

Flagged with enable_le_audio_sharing

Bug: 305620450
Test: Manual
Change-Id: I3d37c87a128098a1b1a38cb8621be9a4d4e8c15e