BroadcastQueue: omit overly noisy trace event.

This method is currently called far too often, and pollutes trace
output.  We have some ideas on how to improve in the future, but
remove the tracing for now.

Bug: 253906105
Test: atest FrameworksMockingServicesTests:BroadcastRecordTest
Test: atest FrameworksMockingServicesTests:BroadcastQueueTest
Test: atest FrameworksMockingServicesTests:BroadcastQueueModernImplTest
Change-Id: I414a55fea626d8f2706603fa6709bbf6f087c758