Add the frequency of the connected AP into the ConnectionAttemptMetadata, the purpose is to judge if there is MCC symptom.

Storage increase will be 4 bytes increasing in ConnetionAttemptMetadata.

(4 bytes in each sharing * 2610000 shares/daily * 7 days/week) / GB = about 0.7 GB)
(2610000 was based on current daily connection attempts count on 20221017.)

PiperOrigin-RevId: 483115234

internal/proto/analytics/connections_log.proto

@@ -463,6 +463,9 @@ message ConnectionsLog {
 
     // The receive buffer size of the created socket
     optional int32 receive_buffer_size = 13;
+
+    // The frequency of the connected WiFi AP.
+    optional int32 connected_ap_frequency = 14;
   }
 }
 // LINT.ThenChange()