BassClient: Handle setting pending broadcast code

Path sets broadcast pending code flage once adding source with broadcast
code.

Test: presubmit
Test: atest BluetoothInstrumentationTests
Test: atest BassClientStateMachineTest
Bug: 150670922
Bug: 229965085
Tag: #feature
Sponsor: jpawlowski@
Change-Id: I8f935ac2928c1f551058cf51e3c3b941a22d678d