Bug 36338: Update onboarding error message when creating the Koha administrator patron

Bug 36338: Update onboarding error message when creating the Koha administrator patron

Update the error message for the web installer onboarding
section when creating the Koha administrator patron (where
the card number or username already exists):
- Fix capitalization
- Use the same label in the error message as used in
  the form

Error message before: The patron has not been created!
Card number or Userid may already exist.

Error message after: The patron was not created! The
card number or username already exists.

Test plan:
1. Option 1:
   1.1 Review the diff for the patch and make sure that
       the updated text makes sense.
       . Previous text: The patron has not been created!
         Card number or Userid may already exist.
       . Updated text: The patron was not created! The
         card number or username already exists.
OR
2. Option 2:
   2.1 Access the database server:
       mysql -uroot -ppassword -hkoha-db-1
   2.2 Drop the koha_kohadev database:
       drop database koha_kohadev;
   2.3 Create the database: create database koha_kohadev;
   2.4 Add privileges (for a real installation this would
       be limited):
       grant all on koha_kohadev.* to koha_kohadev;
   2.5 Restart everything (there may be some errors listed):
       flush_memcached and then restart_all
   2.6 Access the web installer: go to 127.0.0.1:8081
   2.7 Use the database user name and password: get from
       /etc/koha/sites/kohadev/koha-conf.xml
       (default: koha_kohadev, password)
   2.8 Continue through the installation process until you
       reach 'Selecting default settings':
      . Make appropriate selections to use all the sample
        data options and settings
   2.9 For the 'Onboarding' step - Create Koha
       administrator patron:
       . Surname: Acevedo
       . First name: Henry
       . Card number: make up a number that doesn't exist in
         the sample date, for example: 741852963
       . Library: Centerville
       . Patron category: Staff
       . Username: 23529000035676 (this is an existing
         value already in the sample data)
       . Password: a valid password, for example:
         KohaCon2024
       . Confirm password: repeat password used
       . Submit
         ==> Error message before patch: The patron has not
             been created! Card number or Userid may
             already exist.
   2.10 Apply the patch.
   2.11 Repeat step 2.9
   2.12 The error message is now: The patron was not created!
        The card number or username already exists.

3. Sign off.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Lucas Gass <lucas@bywatersolutions.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>