Don't install two copies of kcm_fontinst

This looks like an oversight after switching to use the
kcoreaddons_add_plugin macro.


(cherry picked from commit f8c6099a)

kcms/kfontinst/kcmfontinst/CMakeLists.txt

@@ -18,7 +18,6 @@ target_link_libraries(kcm_fontinst
     X11::X11
 )
 
-install(TARGETS kcm_fontinst  DESTINATION ${KDE_INSTALL_PLUGINDIR})
 install( FILES kcm_fontinst.desktop  DESTINATION  ${KDE_INSTALL_APPDIR} )
 install( FILES kfontinst.knsrc DESTINATION  ${KDE_INSTALL_KNSRCDIR} )