Add aconfig flag for hun cycling animation

Add the aconfig flag for the hun cycling animation for the notification avalanche feature.

Bug: 316404716
Test: atest SystemUITests
Flag: ACONFIG notification_heads_up_cycling DEVELOPMENT
Change-Id: I5520de279c573af0a5e101221d6a4d2a52bbbcfe
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index c845ab3..a91a873 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -25,6 +25,13 @@
 }
 
 flag {
+    name: "notification_heads_up_cycling"
+    namespace: "systemui"
+    description: "Heads-up notification cycling animation for the Notification Avalanche feature."
+    bug: "316404716"
+}
+
+flag {
    name: "notification_minimalism_prototype"
    namespace: "systemui"
    description: "Prototype of notification minimalism; the new 'Intermediate' lockscreen customization proposal."