Add metric to log use of hush gesture

Change-Id: I14578149a79b1455267cb6efc6493c596129032d
Bug: 79537757
Bug: 78665512
Test: manual, builds
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index c22dac8..083598d 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -5969,6 +5969,11 @@
     // OS: P
     FIELD_BATTERY_CHARGE_CYCLES = 1439;
 
+    // ACTION: Hush gesture - volume up + power button
+    // CATEGORY: GLOBAL_SYSTEM_UI
+    // OS: P
+    ACTION_HUSH_GESTURE = 1440;
+
     // ---- End P Constants, all P constants go above this line ----
     // Add new aosp constants above this line.
     // END OF AOSP CONSTANTS