LP#1959716: (follow-up) extend fix to item tags

LP#1959716: (follow-up) extend fix to item tags

To test this patch series:

[1] Set the Angular holdings and item attributes editor to
    unified mode.
[2] Create a new call number and item. Note that the buttons
    to create item tags, item alerts, and item notes do not work.
[3] Apply the patch and repeat step 2.
[4] This time, adding tags, alerts, and notes in the course of
    creating a new item should work.

Signed-off-by: Galen Charlton <gmc@equinoxOLI.org>