Add "preferences-desktop-navigation" icon

Summary:
BUG: 402910
{F7324021}

Test Plan: Search for "preferences-desktop-navigation" in Cuttlefish.

Reviewers: #vdg, ndavis

Reviewed By: #vdg, ndavis

Subscribers: kde-frameworks-devel, #vdg

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D23749