Don't use fetch_default_visibility_levels() method in bp_has_profile() loop

There's no need to do this custom pre-fetching of visibility levels within
the bp_has_profile() loop, because the values are already loaded into the cache
by bp_xprofile_update_meta_cache(). So we use bp_xprofile_get_meta() instead.

See #5398

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7915 cdf35c40-ae34-48e0-9cc9-0c9da1808c22