Context Hub Service: Add reliable message duplicate detection

This CL adds reliable message duplicate detection and
test infrastructure in the ContextHubService to create
duplicates during test mode.

Bug: 331795143
Flag: context_hub.reliable_message_duplicate_detection_service
Test: Run the reliable message test with the
      reliable_message_test_mode_behavior flag
      enabled
Change-Id: I29b8b58787f9c88546b17a99c2738e282dbd53fe