Fix BoundServiceSession bookkeeping

Using a map and an array to maintain an indexed set of tags
with stable indices.

Test: atest FrameworksServicesTests:BoundServiceSessionTests
Test: atest FrameworksServicesTestsRavenwood_ProcessStateController

Flag: android.service.notification.report_nls_start_and_end

Bug: 424474390
Change-Id: I535f1fe2aa88817b0dd8ed9be599b9dd13afe4fd