[Partial Screen Sharing] Fix app selector not animating out when the selected task is the foreground task

Test: MediaProjectionRecentsViewControllerTest
Test: Manual
Fixes: 314385883
Flag: ACONFIG com.android.systemui.pss_app_selector_abrupt_exit_fix DISABLED
Change-Id: Ic4a8f65c168a8a963502da8e71617732968e25a8
diff --git a/packages/SystemUI/aconfig/systemui.aconfig b/packages/SystemUI/aconfig/systemui.aconfig
index f5c4843..f4561a1 100644
--- a/packages/SystemUI/aconfig/systemui.aconfig
+++ b/packages/SystemUI/aconfig/systemui.aconfig
@@ -84,6 +84,17 @@
 }
 
 flag {
+   name: "pss_app_selector_abrupt_exit_fix"
+   namespace: "systemui"
+   description: "Fixes the app selector abruptly disappearing without an animation, when the"
+        "selected task is the foreground task."
+   bug: "314385883"
+   metadata {
+        purpose: PURPOSE_BUGFIX
+   }
+}
+
+flag {
     name: "notifications_background_media_icons"
     namespace: "systemui"
     description: "Updates icons for media notifications in the background."