Bug 18956: (QA follow-up) Resolve a CGI::Param in list context warn

Bug 18956: (QA follow-up) Resolve a CGI::Param in list context warn

From the plack-error.log:
CGI::param called in list context from package CGI::Compile::ROOT::usr_share_koha_masterclone_opac_opac_2dpassword_2drecovery_2epl line 129, this can lead to vulnerabilities. See the warning in "Fetching the value or values of a single named parameter" at /usr/share/perl5/CGI.pm line 436.

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>