Check that widget provider can access RemoteViews URIs

This change responds to a security issue with privileged hosts with
INTERACT_ACROSS_USERS permissions displaying URIs from non-privileged
providers that the provider should not have access to.

Bug: 369137473
Test: Use playground app from bug
Test: atest "CtsAppWidgetTestCases:AppWidgetTest#testCheckRemoteViewsUri"
Flag: android.appwidget.flags.check_remote_views_uri_permission

Change-Id: I9c3f3b0799d2ebdd7a63a54bd2818a6bf37b6e60