Add MODIFY_AUDIO_ROUTING permission to shell for CTS test.

Grant MODIFY_AUDIO_ROUTING permissions to the shell identity
for use within CTS tests.

Bug: 183428114
Test: CTS passed with the permission
Change-Id: I6e8c7553d7fe3263c0345adf0fe67340e5afcbe5
diff --git a/packages/Shell/AndroidManifest.xml b/packages/Shell/AndroidManifest.xml
index 4751095..6cf2bb6 100644
--- a/packages/Shell/AndroidManifest.xml
+++ b/packages/Shell/AndroidManifest.xml
@@ -455,6 +455,9 @@
     <!-- Permission required for CTS test - CtsAlarmManagerTestCases -->
     <uses-permission android:name="android.permission.SCHEDULE_PRIORITIZED_ALARM" />
 
+    <!-- Permission required for CTS test - SystemMediaRouter2Test -->
+    <uses-permission android:name="android.permission.MODIFY_AUDIO_ROUTING" />
+
     <application android:label="@string/app_label"
                 android:theme="@android:style/Theme.DeviceDefault.DayNight"
                 android:defaultToDeviceProtectedStorage="true"