Floss: claim support of LeAudio in HAL as default

As opposed to Android, there is yet the concept of HAL versioning in
Floss, and the HAL should always claim support of LeAudio.

If there is any reason to disable it, that should be done in the policy.

Bug: 317682584
Test: m Bluetooth
Change-Id: I44b4c03f478d9c78959f57085ff765057c747d6b