Components registry is never cleaned up

[thetarnav]

It looks like items added to registry.components and registry.contexts maps are never removed.
And because items for components hold a reference to a signal setter, the signal created in $$component can't ever get garbage collected either.
It's just something I noticed, not sure if this is intended or even a problem in practice.

[lxsmnsyc]

hmm good point, I probably missed this, will check.