LP#1819233 improve AngularJS eg-basic-combo-box filtering

LP#1819233 improve AngularJS eg-basic-combo-box filtering

Adjust the eg-basic-combo-box so that it doesn’t give console errors
when typing characters such as [. Fix the bug that causes it to
sometimes show no results when there are valid results that match.

To test
-------
[1] Apply the patch, then create a new report template, add a
    display field, then open the Change Transform modal.
[2] Verify that the selection box will accept characters like '['
    as input without browser console noise, that the filtering
    is case-insensitive, and that filtering continues to work
    after clicking on the selector.
[3] Instances of this combo box can also be found in the AngularJS
    volume/copy editor.

Signed-off-by: Mike Risher <mrisher@catalyte.io>
Signed-off-by: Terran McCanna <tmccanna@georgialibraries.org>
Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>