Add support for progress bar during unarchival of app.

* With this change, progress bar should appear whenever app update for archived app reaches non-zero progress.
* Once the update is cancelled, the progress bar should also disappear.

Test: PromiseIconUiTest and manually tested the progress bar using Play Store
Bug: 302115555
Flag: ACONFIG com.android.launcher3.enable_support_for_archiving DEVELOPMENT
Change-Id: Iacf7a0fd865dba34915fa09f59c63a1da6e47315
diff --git a/aconfig/launcher.aconfig b/aconfig/launcher.aconfig
index 228c34a..22ed567 100644
--- a/aconfig/launcher.aconfig
+++ b/aconfig/launcher.aconfig
@@ -97,3 +97,10 @@
     description: "Enables full width two pane widget picker for tablets in landscape and portrait"
     bug: "315055849"
 }
+
+flag {
+    name: "enable_support_for_archiving"
+    namespace: "launcher"
+    description: "Enables support for archived apps in Launcher3, such as empty progress bar etc."
+    bug: "210590852"
+}