Fixes for welders and lockers

Welders used to start welding lockers even when off. They didn't finish, but now they won't even begin.

I also tried to tackle https://github.com/tgstation/-tg-station/issues/4187. I am not happy with how I fixed it, but it should sort of work, at least in normal circumstances. do_after() may need a rewrite to fix the issue "properly".
Wait a minute, you have the var only set on using the verb? Come on man, that's retarded. This verb shouldn't even exist. You should tie the var to toggle() or at least open() and close().