[Bluetooth] Convert BluetoothController logs to log buffer so we'll

always have them.

We're mainly interested in the activeDeviceChanged log for b/243755182
but it'll be good to have all the logs.

Bug: 243755182
Fixes: 234774643
Test: dumped log buffer from device
Test: BluetoothControllerImplTest
Change-Id: Id1b12dbf802cae07120f1d6cc2c0b2e3967a1c75