Bug 19641: (follow-up) Fix update child menu option

Bug 19641: (follow-up) Fix update child menu option

This follow-up corrects handling of clicks on the "Update child" menu
option when the patron is an adult. Previously the click handler was
conditionally added via template markup. This patch modifies it to use
the data-tooltip attribute as an indicator that the option is disabled.

To test, apply the patch and clear your browser cache if necessary.

- Open an adult patron's record for viewing.
- Choose More -> Update child from the toolbar menu.
- The menu item should be disabled, and should show a tooltip.
- Clicking the menu item should do nothing.

- Open a child patron's record for viewing.
- Choose More -> Update child from the toolbar menu.
- The patron should be updated to an adult category.

Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>