Add ACTION_SWITCH_DEVICE_UNFOLD to atoms.proto

This allows LatencyTracker to emit that event, and to generate a
dashboard for it.

Bug: 209963184
Test: See ag/16433358
Change-Id: Ia3c570482390ec74fe8d13da6926de0f8dd1ebe2
diff --git a/stats/atoms.proto b/stats/atoms.proto
index 5532a4c..8931391 100644
--- a/stats/atoms.proto
+++ b/stats/atoms.proto
@@ -6362,6 +6362,7 @@
         ACTION_ROTATE_SCREEN_SENSOR = 11;
         ACTION_LOCKSCREEN_UNLOCK = 12;
         ACTION_USER_SWITCH = 13;
+        ACTION_SWITCH_DISPLAY_UNFOLD = 14;
     }
 
     optional ActionType action = 1;