Lp 1735539: Fix Item Status ability to delete multiple copies.

Lp 1735539: Fix Item Status ability to delete multiple copies.

Use the notify handler instead of the resolve handler to collect our
copies.  This ensures we get them all instead of just the last one.

To reproduce the bug:
   1. Open Item Status in the web staff client.
   2. Load multiple items, perhaps by uploading a file of barcodes.
   3. Select more than 1 item from the list.
   4. Choose "Delete Items" from the Actions menu.
   5. Note that the dialog indicates that you will delete 1 copy.
   6. Click the Cancel button in the dialog.

To test, after applying the fix branch:
   1. Open Item Status in the web staff client.
   2. Load multiple items, perhaps by uploading a file of barcodes.
   3. Select more than 1 item from the list.
   4. Choose "Delete Items" from the Actions menu.
   5. Note that that the dialog indicates you will delete X copies,
      where X is the number of items selected.
   6. Click OK and confirm that all copies were deleted.
   7. You can confirm 6 by reloading the interface and uploading the
      file of barcodes again.

Signed-off-by: Jason Stephenson <jason@sigio.com>
Signed-off-by: Jason Boyer <jboyer@library.in.gov>
Signed-off-by: Dan Wells <dbw2@calvin.edu>