router.autoDeleteAge is not accepted in CREATEALIAS command

I've been experimenting with time routed aliases, specifically with the autoDeleteAge feature (SOLR-11925) and notice that the router.autoDeleteAge parameter was silently ignored in the CREATEALIAS command.

Using ALIASPROP to set it worked just fine.

The problem seems to be that TimeRoutedAlias.OPTIONAL_ROUTER_PARAMS has not been updated when the autoDeleteAge property was added.