Fix compile with qt6 (#1475)

Signed-off-by: mosfet80 <[email protected]>

Author: mosfet80

rviz_default_plugins/CMakeLists.txt

@@ -275,7 +275,6 @@ target_link_libraries(rviz_default_plugins PUBLIC
   ${visualization_msgs_TARGETS}
   resource_retriever::resource_retriever
   ${rviz_resource_interfaces_TARGETS}
-  Qt5::Widgets
 )
 
 target_link_libraries(rviz_default_plugins PRIVATE
@@ -395,7 +394,7 @@ if(BUILD_TESTING)
     target_link_libraries(frame_view_controller_test
       ${TEST_FIXTURE_WITH_MOCK_LIBRARIES}
       rviz_default_plugins
-      Qt5::Widgets
+      Qt${QT_VERSION_MAJOR}::Widgets
       ogre_testing_environment
     )
   endif()