force linking against "Release" version of DDS libraries

FindRTIConnextDDS.cmake

```cmake

 if (NOT RTIConnextDDS_FOUND)
        find_package(RTIConnextDDS "6.1.0" EXACT REQUIRED COMPONENTS core)
        # use always the release configuration of RTI libs regardless of current
        # CMAKE_BUILD_TYPE (root cause of double free error)
        set_target_properties(RTIConnextDDS::core PROPERTIES
            MAP_IMPORTED_CONFIG_RELEASE Release
            MAP_IMPORTED_CONFIG_DEBUG Release
            MAP_IMPORTED_CONFIG_RELWITHDEBUGINFO Release)
        set_target_properties(RTIConnextDDS::c_api PROPERTIES
            MAP_IMPORTED_CONFIG_RELEASE Release
            MAP_IMPORTED_CONFIG_DEBUG Release
            MAP_IMPORTED_CONFIG_RELWITHDEBUGINFO Release)
        set_target_properties(RTIConnextDDS::cpp_api PROPERTIES
            MAP_IMPORTED_CONFIG_RELEASE Release
            MAP_IMPORTED_CONFIG_DEBUG Release
            MAP_IMPORTED_CONFIG_RELWITHDEBUGINFO Release)
        set_target_properties(RTIConnextDDS::cpp2_api PROPERTIES
            MAP_IMPORTED_CONFIG_RELEASE Release
            MAP_IMPORTED_CONFIG_DEBUG Release
            MAP_IMPORTED_CONFIG_RELWITHDEBUGINFO Release)
    endif()
```