remote submix: force pipe shutdown on input close

Force mono pipe shutdown when all input stream clients are closed
so that a pending write is not stuck waiting for available buffer.

Bug: 119057550
Test: abort search on BLE remote
Merged-In: I4391e73874e502da5000b1746436fb61bb2fe869
Change-Id: I4391e73874e502da5000b1746436fb61bb2fe869
1 file changed