[le audio] Bass fix the PA syncInfoRequest for local broadcast

getCurrentBroadcastMetadata could return null for newly reconnected device.
This CL fixes a bug in BASS client where it fails to
initiate local broadcast PAST.
This change also exposed one issue with mBassStateReady which needs to be set before notifying the service.

Bug: 400635791
Flag: EXEMPT, trivial fix covered by unit tests
Test: atest BassClientStateMachineTest
Test: manually tested with device reconnected during broadcast
Change-Id: I814ade5b4e0220e0655dc4e63460078ef66c21c6