ActiveDeviceManager: Update tracking connected devices

Let's avoid updating mLeAudioConnectedDevices during LE active device changes.
Instead, we should keep the connected list logic synchronized exclusively within
profileConnectionStateChange.

Bug: 375050065
Test: atest ActiveDeviceManagerTest
Flag: EXEMPT; simple fix, covered by unit tests
Change-Id: I36cec058e965d77684d0a968c11b1c9776e26c95