BassClient: Fix using Metadata cache

Fixes the following:
 - the container is never initialized
 - sourceId to metadata map has no remote context

Bug: 229965085
Bug: 150670922
Tag: #feature
Sponsor: jpawlowski@
Test: atest BluetoothInstrumentationTests
Change-Id: I5dc6275841cecc6851e461cb29f1d9f53724be89
(cherry picked from commit 99f9def1)