Add constant for bluetooth fragment

simply adds a metrics constant for the new bluetooth screen

Bug: 77543471
Test: robotests pass
Merged-In: Id6317df4b86def4e0aa095fd3bc1ed544c0f0220
Change-Id: Id6317df4b86def4e0aa095fd3bc1ed544c0f0220

proto/src/metrics_constants.proto

@@ -5659,6 +5659,11 @@ message MetricsEvent {
     // OS: P
     FIELD_APP_VERSION_CODE = 1389;
 
+    // OPEN: Settings > Connected Devices > Bluetooth
+    // CATEGORY: SETTINGS
+    // OS: P
+    BLUETOOTH_FRAGMENT = 1390;
+
     // ---- End P Constants, all P constants go above this line ----
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS