Hide 'Field Name' screen-reader-text on xProfile field edit when a title exists.

This ensures that we don't see overlapping text in the case of existing fields.

See [9084].

Fixes #6073.

git-svn-id: https://buddypress.svn.wordpress.org/trunk@9235 cdf35c40-ae34-48e0-9cc9-0c9da1808c22