Add smartspace card received_latency_millis metric to atom

Test: manual verify
Bug: 198305799
Change-Id: Iefafe54dc7fdb6af4c06c89f6296cb8556016deb
diff --git a/stats/atoms.proto b/stats/atoms.proto
index 211e344..0e50135 100644
--- a/stats/atoms.proto
+++ b/stats/atoms.proto
@@ -3603,6 +3603,9 @@
     // If multiple subcards are displayed simultaneously, the number of subcards
     // shown when the interaction occurred.
     optional int32 interacted_subcard_cardinality = 10;
+    // The time it takes in ms from smartspace target is created to sysui receives
+    // the target.
+    optional int32 received_latency_millis = 11;
 }
 
 /**