Does the Battery Service Client (ble_bas_c) module handle subscribing to notifications from multiple slaves? In my use case, I have the nRF52840 dev kit connecting to multiple peripherals and each of them has the Battery Service. I need to subscribe and get notified of changes in each of their battery levels. Is this possible with the code as it currently stands? or does it require any modifications to make it work? If so, can you provide some guidance on what needs to change?