Allow building with -DCMAKE_DISABLE_FIND_PACKAGE_KF5KDELibs4Support=TRUE
The dateandtim KCM still needs KDELibs4Support, but I am not able to build kdelibs4support for my cross-compiled target (Arm Morello). This patch allows me to disable the dependency and skip building the dateandtime KCM by explicitly passing -DCMAKE_DISABLE_FIND_PACKAGE_KF5KDELibs4Support=TRUE.