Use the Modes icon in the "dummy" ModesActivity

So that newly-created Modes Settings shortcuts have it (a different CL will update previous shortcuts).

Bug: 365545604
Change-Id: I74760bde4c40646b0571e0b7dad6383729f470f7
Test: manual
Flag: android.app.modes_ui
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 66c3beb..3527e83 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -1293,7 +1293,7 @@
         <activity
             android:name="Settings$ModesSettingsActivity"
             android:label="@string/zen_modes_list_title"
-            android:icon="@drawable/ic_homepage_notification"
+            android:icon="@*android:drawable/ic_zen_priority_modes"
             android:exported="true">
             <intent-filter android:priority="1"
                            android:featureFlag="android.app.modes_ui">