[Audiosharing] Check broadcast id before return cached metadata

When caller getLatestBluetoothLeBroadcastMetadata between
onBroadcastStarted and onBroadcastMetadataChanged, they could get a
staled cached metadata. In this case we need call broadcast api to fetch
the latest metadata.

Bug: 400803742
Test: atest
Flag: EXEMPT bug fix
Change-Id: I25bd8f75ce6913c6c6fb3c4620e96e077a9a0953