LP#1752665: suppress located URIs in holdings view

LP#1752665: suppress located URIs in holdings view

To test:

[1] Locate or create a bibliographic record that has at least
    one located URI (e.g., an 856 with a $9 containing an org
    unit code)
[2] View the record in the Holdings View in the web staff interface,
    with the 'Show empty call numbers' (or volumes) option
    selected.
[3] Note that rows are displayed with a call number label of '##URI##';
    these are for the located URIs and should not be visible here.
[4] Apply the patch and repeat step 2. This time the '##URI##' entries
    should not display.

Signed-off-by: Jeff Davis <jdavis@sitka.bclibraries.ca>
Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>