Add connection attempt type into the established connection for distinguishing the initial and upgrade in the pipeline. So we could get the information of:

1. the transfer speed in initial connection stage or upgraded stage.
2. when doing the end to end mapping, we could map the right metadate field into right established connection for getting more correct analysis.

PiperOrigin-RevId: 451156631

internal/proto/analytics/connections_log.proto

@@ -284,6 +284,9 @@ message ConnectionsLog {
 
     // The token use to identify this established connection.
     optional string connection_token = 7;
+
+    // The type of established connection.
+    optional location.nearby.proto.connections.ConnectionAttemptType type = 8;
   }
 
   // A Payload transferred (or attempted to be transferred) between devices.