Add qt6-wayland-dev dependency
KWindowSystem needs QtWaylandClient for KWaylandExtras now.
Should fix https://build.neon.kde.org/job/jammy_unstable_kf6_kf6-kwindowsystem_bin_amd64/72/console
20:36:46 CMake Error at CMakeLists.txt:65 (find_package):
20:36:46 Could not find a package configuration file provided by "Qt6WaylandClient"
20:36:46 (requested version 6.5.0) with any of the following names:
20:36:46
20:36:46 Qt6WaylandClientConfig.cmake
20:36:46 qt6waylandclient-config.cmake
20:36:46
20:36:46 Add the installation prefix of "Qt6WaylandClient" to CMAKE_PREFIX_PATH or
20:36:46 set "Qt6WaylandClient_DIR" to a directory containing one of the above
20:36:46 files. If "Qt6WaylandClient" provides a separate development package or
20:36:46 SDK, be sure it has been installed.