LP1965065 Example DOB on self-registration displays twice

LP1965065 Example DOB on self-registration displays twice

This fixes the double display of the example text in the self-registration form of the opac.
Not only does DOB exmaple display twice but the example text for phone, email, and
postal code also display twice.

To test:
1. Go to library settings and set "Allow Patron Self Registration" and "Show DOB field on patron
registration" to true.  Set a value for "Example dob field on patron registration".  If testing
phone, postal code, or email the appropriate values must be set for the show and example
parameters.
2. Go to "Request a Library Card" in the opac.
3. Notice that the DOB example displays twice.
4. Apply the patch.
5. The example now just displays once.

Signed-off-by: Garry Collum <gcollum@gmail.com>