Use it instead of classname::getImplementation from UNO3_GETIMPLEMENTATION_*
Change-Id: Ifcc8cfcd6369c576250008c76ce31ba79ea3a596
Reviewed-on: https://gerrit.libreoffice.org/74107
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>