Fix favicons in firefox bookmarks runner

Summary:
The favicons are located in the file favicons.sqlite file since FF 37 and the old table was removed in FF 41 resulting in crashes because the table wasn't found.

* Update SQL to match the tables in FF 58
* query.bindValue() needs a double colon in the string, see https://doc.qt.io/qt-5/qsqlquery.html#prepare
* Fix intendation (tab->spaces) in one line

BUG: 363136

Test Plan:
Firefox bookmark favicons now work and don't crash Krunner and Kickoff
{F5715653}

{F5715654}

Reviewers: #plasma, broulik, davidedmundson

Reviewed By: #plasma, davidedmundson

Subscribers: ngraham, elvisangelaccio, davidedmundson, plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D10610