Disable landscape mode for picker

This CL aims at disabling landscape mode for picker2 activity.
Landscape mode is currently not supported for picker and therefore
setting this flag helps to disable rotation to landscape mode.

Bug: 391986843
Flag: com.android.systemui.shared.new_customization_picker_ui
Test: Tested by building & installing picker on local and checking if
landscape rotation is happening

Change-Id: I155e3ac5f196c043555576b5efc691f415316afe
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index f89ff6e..8812bec 100755
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -85,6 +85,7 @@
             android:name="com.android.wallpaper.picker.customization.ui.CustomizationPickerActivity2"
             android:label="@string/app_name"
             android:relinquishTaskIdentity="true"
+            android:screenOrientation="portrait"
             android:resizeableActivity="false"
             android:theme="@style/WallpaperTheme"
             android:configChanges="assetsPaths"