Bug 32555: Fix serial vs. serialitem typo

Bug 32555: Fix serial vs. serialitem typo

To test:
1. Create a serial subscription
   1.1. Go to Serials
   1.2. Click on New subscription
   1.3. Fill out the first form
        - Vendor: leave empty
        - Record: enter a record number (I used 108)
        - Create an item record when receiving this serial
        - When there is an irregular issue: Keep issue number
        - Manual history: leave unchecked
        - Call number: leave empty
        - Library: Centerville
        - Public/nonpublic note: leave empty
        - Patron notification: None
        - Location: None
        - Collection: None
        - Item type: Continuing resources
        - Grace period: leave empty
        - Number of issues to display: leave both empty
   1.4. Click Next (and confirm you are not using a vendor)
   1.5. Fill out the second form
        - First issue publication date: 2023-01-01
        - Frequency: 1/month
        - Subscription length: issues 12
        - Subscription start date: 2023-01-01
        - Subscription end date: 2024-01-01
        - Numbering pattern: Number
        - Locale: leave empty
        - Begins with: 42
        - Inner counter: leave empty
   1.6. Click Test prediction pattern
   1.7. Click Save subscription
2. Click OPAC view: Open in new window.
=> SUCCESS: It should open normally in another tab/window and the record displays without problem
3. Back in the staff interface tab, receive an issue
   3.1. Click Receive
   3.2. In Status, choose Arrived for No. 42
   3.3. Click Save
4. Go back to the OPAC tab and refresh
=> FAIL: Page explodes
5. Apply this patch
6. Repeat 4
=> SUCCESS: Information shows correctly no explosions.
7. Sign off :-D

Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Caroline Cyr La Rose <caroline.cyr-la-rose@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>