Add a new flag so that we can switch and avoid teamfood problems

Test: n/a
Flag: com.android.systemui.notification_avalanche_throttle_hun
Bug: 307288824
Change-Id: Ie700b2e5e08d602b48779b9f798e72da762dd88f
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 36bad5e..25ba9c5 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -184,6 +184,13 @@
 }
 
 flag {
+    name: "notification_avalanche_throttle_hun"
+    namespace: "systemui"
+    description: "(currently unused) During notification avalanche, throttle HUNs showing in fast succession."
+    bug: "307288824"
+}
+
+flag {
     name: "notification_avalanche_suppression"
     namespace: "systemui"
     description: "After notification avalanche floodgate event, suppress HUNs completely."