Add `AvailableAudioSharingMediaDeviceItem` for devices that could either do...

Add `AvailableAudioSharingMediaDeviceItem` for devices that could either do audio sharing, or be set as an active media device.

This kind of device will use a fixed device summary "Tap to switch or share audio", and will pop up a dialog upon click (implement in the next CL).

Test: atest
Bug: 360753165
Flag: com.android.settingslib.flags.enable_le_audio_sharing
Change-Id: I6150c23ebc698b038ee35930eb3b4bda4d83bb22