LP1907974: Updating call numbers in course module reflected in grid

LP1907974: Updating call numbers in course module reflected in grid

Also:
  * refactors the updateItem method for more idiomatic RxJS usage (e.g.
    no nested subscribes)
  * corrects some Boolean, String, and Number types to boolean, string,
    and number (to use the primitive types instead of objects, as
    recommended by the Typescript handbook:
    https://www.typescriptlang.org/docs/handbook/basic-types.html#about-number-string-boolean-symbol-and-object)

To test:

1) Go to Local Admin > Course List
2) Double click on a course
3) Go to the materials tab
4) Add an item by barcode, making sure to supply a temporary call
   number, and that the call number checkbox is checked.
5) Note that the grid on the right display's the item's old call number,
   not its new one.
6) Apply this patch.
7) Repeat step 4.  Note that the temporary call number is reflected in
   the grid now.

Signed-off-by: Jane Sandberg <sandbej@linnbenton.edu>
Signed-off-by: Michele Morgan <mmorgan@noblenet.org>