Bug 19911: Escape password value during self-registration confirmation

Bug 19911: Escape password value during self-registration confirmation

The password must be correctly escape, it can contains html character
and break the display.

Test plan:
Apply first patch and confirm that the display is broken
Apply second patch (this one) and confirm that the display is fixed

Signed-off-by: Arturo <alongoria@sll.texas.gov>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit f6adfb4257d0326a101771246777b10965632bc8)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>