Make system gallery role invisible (and non-requestable).

Bug: 144307267
Test: system gallery is dumped and hidden in UI
Change-Id: I483c25e0ed230ef9c184f6abc519ec87336b0a42
diff --git a/PermissionController/res/xml/roles.xml b/PermissionController/res/xml/roles.xml
index 5206f99..b005306 100644
--- a/PermissionController/res/xml/roles.xml
+++ b/PermissionController/res/xml/roles.xml
@@ -423,7 +423,8 @@
         name="android.app.role.SYSTEM_GALLERY"
         defaultHolders="config_systemGallery"
         exclusive="true"
-        systemOnly="true">
+        systemOnly="true"
+        visible="false">
         <permissions>
             <permission-set name="storage" />
             <permission name="android.permission.ACCESS_MEDIA_LOCATION" />