refactor(core): Removed Arc from sigs where not required

[alexsnaps]

Moved the Arc::clone on the call site, as it isn't "optional", spawn_config_watcher needs to hold on to the Arc, from the spawn_watcher call.
otoh, register_protocols doesn't need an Arc at all, "only" requires to borrow the ref to ListenerPipelines.

Makes the code easier to read, as to what the contract on each of those calls are (without needing to dig, potentially deep, into the call tree) wrt ownership & lifetimes. I think that's generally desirable.

There are a few other places where this could be aligned, if this makes sense to all. wdyt @shaneutt @twghu

[alexsnaps]

Darn... Sorry, looks like I have a stale main 🤦
Question remains relevant, but not this PR, let me close and see if it even matters still, looks like all is in ServerState now. Sorry about this again...