FindBoost: Make imported targets fall back to Release

FindBoost only detects Debug and Release configurations.  All other
configurations will fall back to the configuration listed as the first
entry in `IMPORTED_CONFIGURATIONS`.  Switch the order so that `Release`
is listed first, as this is a better fallback than `Debug` for the
`RelWithDebInfo` and `MinSizeRel` configurations.  See issue #16091.

Modules/FindBoost.cmake

@@ -1734,20 +1734,20 @@ if(Boost_FOUND)
             IMPORTED_LINK_INTERFACE_LANGUAGES "CXX"
             IMPORTED_LOCATION "${Boost_${UPPERCOMPONENT}_LIBRARY}")
         endif()
-        if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
-          set_property(TARGET Boost::${COMPONENT} APPEND PROPERTY
-            IMPORTED_CONFIGURATIONS DEBUG)
-          set_target_properties(Boost::${COMPONENT} PROPERTIES
-            IMPORTED_LINK_INTERFACE_LANGUAGES_DEBUG "CXX"
-            IMPORTED_LOCATION_DEBUG "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
-        endif()
         if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE}")
           set_property(TARGET Boost::${COMPONENT} APPEND PROPERTY
             IMPORTED_CONFIGURATIONS RELEASE)
           set_target_properties(Boost::${COMPONENT} PROPERTIES
             IMPORTED_LINK_INTERFACE_LANGUAGES_RELEASE "CXX"
             IMPORTED_LOCATION_RELEASE "${Boost_${UPPERCOMPONENT}_LIBRARY_RELEASE}")
         endif()
+        if(EXISTS "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
+          set_property(TARGET Boost::${COMPONENT} APPEND PROPERTY
+            IMPORTED_CONFIGURATIONS DEBUG)
+          set_target_properties(Boost::${COMPONENT} PROPERTIES
+            IMPORTED_LINK_INTERFACE_LANGUAGES_DEBUG "CXX"
+            IMPORTED_LOCATION_DEBUG "${Boost_${UPPERCOMPONENT}_LIBRARY_DEBUG}")
+        endif()
         if(_Boost_${UPPERCOMPONENT}_DEPENDENCIES)
           unset(_Boost_${UPPERCOMPONENT}_TARGET_DEPENDENCIES)
           foreach(dep ${_Boost_${UPPERCOMPONENT}_DEPENDENCIES})