LdapUrl: fix LDAP queries broken with non-ascii search strings.
Summary:
Qt5 made query() return a PrettyDecoded query string, while the code
was calling fromPercentEncoding for the filter, i.e. assuming it to be FullyEncoded.
With unittest
Test Plan: Typing Valérie in kmail composer now finds LDAP completion correctly.
Reviewers: dvratil, mlaurent
Reviewed By: dvratil
Subscribers: KDE PIM
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D12387