Add metric for bluetooth pairing page

Bug: 38383542
Test: Build
Change-Id: Iabc31726528ce8348858cb0aabf5defecee8ea04
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index 2eb94d3..63e5cac 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -4114,6 +4114,11 @@
     // OS: O DR
     ACTION_OPEN_APP_SETTING = 1017;
 
+    // OPEN: Settings > Connected devices > Bluetooth > Pair new device
+    // CATEGORY: SETTINGS
+    // OS: O DR
+    BLUETOOTH_PAIRING = 1018;
+
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS
   }