McsService: Fix authorization issues

With this patch, known le audio device got authorized in MCS when added
to the group.
This patch also makes sure that authorization is set when Bluetooth is
enabled.

Bug: 254192601
Test: atest BluetoothInstrumentationTests
Tag: #feature

Change-Id: I969578802afec4722e3a0d9f946d79384d80a941