Bug https://bugs.kde.org/show_bug.cgi?id=410190 describes the inconsistent virtual desktop numbering between the Switch Window popup and the taskbar Move To Desktop list. This patch fixes the Switch Window popup to use the more natural (to the user) 1-based desktop IDs.
According to virtualdesktopinfo.h, a desktop ID on Wayland is a QString while on X11 it is a uint. Therefore using toString() here for correct formatting of the desktop ID on both X11 and Wayland.
CCBUG: 410190