Fix live timers flickering when pausing

This change adds a flag which uses a stable id as the key for timers,
instead of using the smartspace target id. The stable id stays the same
when pausing/playing timers, which allows us to re-use the existing
AndroidView of the timer instead of creating a new one.

Bug: 353801573
Test: atest SystemUiRoboTests
Flag: com.android.systemui.communal_timer_flicker_fix
Change-Id: I1124a9148ddd635899eb5d9f6780cd49add9f232
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index 27f4305..1f1495a 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -1005,6 +1005,16 @@
 }
 
 flag {
+  name: "communal_timer_flicker_fix"
+  namespace: "systemui"
+  description: "fixes timers on the hub flickering when pausing"
+  bug: "353801573"
+  metadata {
+    purpose: PURPOSE_BUGFIX
+  }
+}
+
+flag {
   name: "app_clips_backlinks"
   namespace: "systemui"
   description: "Enables Backlinks improvement feature in App Clips"