MediaMetrics: Prepare audio device usage protos for statsd

MediaMetricsAudioRecordDeviceUsageReported
MediaMetricsAudioThreadDeviceUsageReported
MediaMetricsAudioTrackDeviceUsageReported
MediaMetricsAudioDeviceConnectionReported

Add track traits to identify static AudioTracks.
Fix AudioTrack/AudioRecord flag communication.
Move debug logging to verbose (delivered protos show in dumpsys).
Unknown strings which fail validation become empty.
Test statsd type validation.

Test: atest mediametrics_tests
Test: adb shell dumpsys media.metrics (after BT connection)
Test: statsd_testdrive (294-297)
Bug: 149850236
Change-Id: I53c5d18a346af54941007b9938a8ab10e34b7038