Move notifying powerManager userActivity to background thread

Test: checked perfetto binder transaction
Bug: 325203885
Flag: ACONFIG com.android.systemui.notify_power_manager_user_activity_background DEVELOPMENT

Change-Id: I5d9cc4a563748b2d07c9f6cac99ad271aebba58b
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index a69a2a6..f5c4843 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -546,3 +546,13 @@
         purpose: PURPOSE_BUGFIX
     }
 }
+
+flag {
+    name: "notify_power_manager_user_activity_background"
+    namespace: "systemui"
+    description: "Decide whether to notify the user activity to power manager in the background thread."
+    bug: "325203885"
+    metadata {
+        purpose: PURPOSE_BUGFIX
+    }
+}