kf5-base-applications: Drop khelpcenter
KHelpCenter isn't needed for a minimal desktop build. When khelpcenter is not installed, the various "Help" buttons in apps will simply open the online version of the documentation in the default browser.
KHelpCenter isn't needed for a minimal desktop build. When khelpcenter is not installed, the various "Help" buttons in apps will simply open the online version of the documentation in the default browser.