LP1878079 Staffcat Add Call Nums honors selected orgs

LP1878079 Staffcat Add Call Nums honors selected orgs

When adding new call numbers from the Angular staff catalog Holdings
View grid, take all selected grid rows into consideration when
determining how many call numbers to add and what their owning libs
should be.

To test:
* Navigate to the Holdings View tab of a record detail page in the Angular
  staff catalog.
* Select multiple rows in the grid which are org unit-only rows (i.e.
  the row does not refer to a specific call number or item).
* From the action menu / right client menu, select "Add Callnumbers"
* Confirm that a call number entry for each selected org unit is present
  in the spawned holdings editor.

Signed-off-by: Bill Erickson <berickxx@gmail.com>