LP#1955065: fix deletion of item notes in Angular item attributes editor

LP#1955065: fix deletion of item notes in Angular item attributes editor

This patch fixes several bugs that prevent item notes from
being correctly deleted by the Angular item attributes editor.

To test
-------
[1] Apply patch.
[2] Edit a single item in the Angular item attributes editor.
[3] Verify that notes can be added and deleted.
[4] In Holdings View, choose Add/Manage Item Notes for a single
    selected item.
[5] Verify that notes can be added and deleted;
[6] Repeat steps 4 and 5 for a different item after successfully
    deleting an item note. Verify that notes can be added and deleted.
[7] In Holdings View, choose Add/Manage Item Notes for multiple
    selected items.
[8] Verify that ntoes can be added to the selected items.

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