Log UsbDeviceAttached events for Audio devices

UsbDeviceAttached is logged when the device has an audio interface.
Info such as VID, PID, whether the device has hid or mass storage
interface and the duration for which the usb device was connected
would be logged as well.

Bug: 118783261
Test: Manually tested by running: adb shell cmd stats print-logs,
    adb logcat | grep statsd | grep \(77\)
Change-Id: I57bbfd22ef377553daa113968fe53c4fe0f8e4d2
diff --git a/stats/atoms.proto b/stats/atoms.proto
index 41a2021..d5a32bd 100644
--- a/stats/atoms.proto
+++ b/stats/atoms.proto
@@ -1207,6 +1207,12 @@
     optional bool has_audio = 3;
     optional bool has_hid = 4;
     optional bool has_storage = 5;
+    enum State {
+        STATE_DISCONNECTED = 0;
+        STATE_CONNECTED = 1;
+    }
+    optional State state = 6;
+    optional int64 last_connect_duration_ms = 7;
 }