Grant SET_WALLPAPER_DIM_AMOUNT permission to shell

Test: atest
Bug: 202841384
Change-Id: I25956393d5291f3b8f49bacead579975466e150e
diff --git a/packages/Shell/AndroidManifest.xml b/packages/Shell/AndroidManifest.xml
index 1303a62..8546b16 100644
--- a/packages/Shell/AndroidManifest.xml
+++ b/packages/Shell/AndroidManifest.xml
@@ -341,6 +341,9 @@
     <uses-permission android:name="android.permission.SET_WALLPAPER" />
     <uses-permission android:name="android.permission.SET_WALLPAPER_COMPONENT" />
 
+    <!-- Permission needed to test wallpaper dimming -->
+    <uses-permission android:name="android.permission.SET_WALLPAPER_DIM_AMOUNT" />
+
     <!-- Permission required to test ContentResolver caching. -->
     <uses-permission android:name="android.permission.CACHE_CONTENT" />