Bug 37332: Fix unseen and customer renewal date parameters in svc

Bug 37332: Fix unseen and customer renewal date parameters in svc

To test:
0. Enable unseen renewals
    i. Set the system preference UnseenRenewals to Allowed
    ii. Edit the circulation rules to specify the maximum number of
        unseen renewals allowed
1. Check out an item to a patron
2. In the checkouts table on that patron's account, check the "Renew"
   checkbox for that item
3. Select a custom renewal date using the Renewal due date flatpicker
4. Check the checkbox labeled "Renew as unseen if appropriate"
4. Click Renew selected items
--> The item renews, but its new due date follows the renewal period
    specified in the circulation rules, regardless of what date was
    entered in the Renewal due date field
--> The checkout still has all of its unseen renewals remaining,
    indicating that the renewal was not processed as an unseen renewal
5. Enter another custom renewal date and renew checkout with the Renew
   all button
--> Same result
6. Apply patch and restart_all
7. Repeat test plan
--> Custom renewal date is now respected
--> Number of unseen renewals remaining decreases when "Renew as unseen"
    checkbox is checked
8. Renew the item with the "Renew as unseen" checkbox unchecked
--> Confirm that number of unseen renewals is reset (i.e. the checkout
    once again has all of its unseen renewals remaining), indicating
    that the renewal was processed as a "seen" renewal

Signed-off-by: CJ Lynce <cj.lynce@westlakelibrary.org>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>