Add support for 'user_id' param to bp_get_the_profile_field_options()

This allows the use of this template function outside of the front-end Edit
Profile page, where $bp->displayed_user->id is defined.

See #5197

git-svn-id: https://buddypress.svn.wordpress.org/trunk@7762 cdf35c40-ae34-48e0-9cc9-0c9da1808c22