Add PNN in the metrics for carrier ID mismatch.

Bug: 169273187
Test: manual
Change-Id: I5e7d88939a88e7eaa4e68220e81d21fad865ff01
diff --git a/stats/atoms.proto b/stats/atoms.proto
index 3d67e65..a73e26e 100644
--- a/stats/atoms.proto
+++ b/stats/atoms.proto
@@ -10736,6 +10736,10 @@
 
     // SPN value of the SIM card.
     optional string spn = 4;
+
+    // First record of the PNN in the SIM card. This field is populated only if the SPN is missing
+    // or empty.
+    optional string pnn = 5;
 }
 
 /**