Bug 34082: Cut some redundancy in OPAC JavaScript string translations

Bug 34082: Cut some redundancy in OPAC JavaScript string translations

This patch consolidates some JS code so that we're not defining a string
ine one place and using it once elsewhere. With JS-friendly translations
tools we don't need this workaround.

To test, apply the patch and go to Administration -> Circulation and
fine rules.

- Configure an item type rule with the "OPAC item level holds" setting
  set to "Force."
- Log in to the OPAC and locate a record with that item type and
  multiple items. An example in the sample data:
  /cgi-bin/koha/opac-detail.pl?biblionumber=12
- Place a hold on the item.
  - The holds screen should show a table of items.
  - Open your browser's developer tools.
  - In the Console tab, paste in this code and hit ENTER:

    $(".checkitem").prop("checked", false);

  - All radio buttons in the table of items should be cleared.
- Click the "Confirm hold" button. You should get an alert:
  "Expecting a specific item selection."

- Log in to the OPAC and click the "Search history" tab from the user
  summary page.
- Check one or more checkboxes next to search history items and click
  the "Remove selected searches."
  - You should get an alert: "Are you sure you want to delete selected
    search history entries?"

- Log in to the OPAC, create a new list if necessary, and add some
  titles to the list.
- Test that confirmation messages show correctly:
  - Deleting a single title by clicking the "Remove
    from this list" link.
  - Deleting multiple titles by checking boxes and
    clicking "Remove from list."
  - Deleting a list.

- In Administration -> System preferences, enable TagsEnabled if
  necessary.
- Log in to the OPAC and tag one or more items.
- From the Tag cloud page, check one or more boxes for your tags, and
  click the "Delete selected tags" button at the bottom of the page.
- The confirmation message should display correctly.

- To test the change to opac-account.tt you have to install a payment
  plugin, e.g.
  https://gitlab.com/thekesolutions/plugins/koha-plugin-pay-via-paypal,
  and attempt to submit a payment which is below the minimum payment
  threshold set in the plugin's configuration.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>