Add INTERACT_ACROSS_USERS permission for DocsUI

Test: make aosp_x86_64-eng
Test: check INTERACT_ACROSS_USERS in /system/etc/permissions/com.android.documentsui.xml
Test: check INTERACT_ACROSS_USERS grant to DocumentsUI.apk
Test: atest DocumentsUITests:com.android.documentsui.PermissionsTest
Bug: 148198996
Change-Id: I6bcef56c508b3fad7a56cdc629089a36f4cdbec5

data/etc/com.android.documentsui.xml

@@ -17,5 +17,6 @@
 <permissions>
     <privapp-permissions package="com.android.documentsui">
         <permission name="android.permission.CHANGE_OVERLAY_PACKAGES"/>
+        <permission name="android.permission.INTERACT_ACROSS_USERS"/>
     </privapp-permissions>
 </permissions>