kde/kf6-extra-cmake-modules: rebase to 6.28.0 (ECM) + teach version parser set(VERSION)

kf6-kcoreaddons 6.28.0 requires ECM >= 6.28.0 but the vendored ECM source/ was
still 6.10.0: the sync engine skipped it because ECM's version marker is a bare
set(VERSION "X.Y.Z") that the parser didn't recognize (only KF_VERSION /
PROJECT_VERSION / RELEASE_SERVICE_VERSION). Re-lay ECM from its 6.28.0 source.tar
(pure cmake modules, no Redox port) and teach both the sync engine and the
validator to read set(VERSION) so this class is caught, not silently skipped.

local/recipes/kde/kf6-extra-cmake-modules/source/modules/ECMFindModuleHelpers.cmake

@@ -103,6 +103,8 @@ The following variables will be set:
 Since pre-1.0.0.
 #]=======================================================================]
 
+cmake_policy(VERSION 3.16)
+
 macro(ecm_find_package_version_check module_name)
     if(CMAKE_VERSION VERSION_LESS 3.16.0)
         message(FATAL_ERROR "CMake 3.16.0 is required by Find${module_name}.cmake")
@@ -257,6 +259,11 @@ macro(ecm_find_package_handle_library_components module_name)
                     INTERFACE_INCLUDE_DIRECTORIES "${${module_name}_${ecm_fpwc_comp}_INCLUDE_DIR}"
                     INTERFACE_LINK_LIBRARIES "${ecm_fpwc_dep_targets}"
                 )
+                if("${${module_name}_${ecm_fpwc_comp}_LIBRARY}" MATCHES "\\${CMAKE_STATIC_LIBRARY_SUFFIX}$")
+                    set_target_properties(${module_name}::${ecm_fpwc_comp} PROPERTIES
+                        INTERFACE_LINK_LIBRARIES "${PKG_${module_name}_${ecm_fpwc_comp}_LINK_LIBRARIES}"
+                    )
+                endif()
             endif()
             list(APPEND ${module_name}_TARGETS
                         "${module_name}::${ecm_fpwc_comp}")