metrics: num saved networks with mac randomization

Bug: 124121205
Test: unit tests
Test: dumpsys wifi
Change-Id: I6bba5bc6fcd78bfd5bbd4ebbda409999dd40d151
diff --git a/proto/src/wifi.proto b/proto/src/wifi.proto
index 82359c5..ad0ed8b 100644
--- a/proto/src/wifi.proto
+++ b/proto/src/wifi.proto
@@ -518,6 +518,9 @@
 
   // WifiConfigStore read/write metrics.
   optional WifiConfigStoreIO wifi_config_store_io = 137;
+
+  // Total number of saved networks with mac randomization enabled.
+  optional int32 num_saved_networks_with_mac_randomization = 138;
 }
 
 // Information that gets logged for every WiFi connection.