fix(pm/wiki): correct service configuration

Doing this as a oneshot means that on switch-ing configuration, the
service never "comes up" (as it gets stuck in the --wait). It's far
better to just have a standard service that is restarted by a timer when
it exits rather than a oneshot here...

packetmix/systems/teal/wiki.nix

···
       ${config.services.phpfpm.pools.mediawiki.phpPackage}/bin/php ${config.services.mediawiki.finalPackage}/share/mediawiki/maintenance/run.php runJobs --memory-limit 1G --wait
     '';
     serviceConfig = {
-      RemainAfterExit = false;
-      Type = "oneshot";
       User = "mediawiki";
       Group = "nginx";
       PrivateTmp = true;