Registry in crux_core::bridge::Bridge leaks Never and Many Requests

[DeltaEvo]

Requests are only removed from the registry when they are resumed and the Resolve handle is swapped to Never. This only happens for Once Resolve handles but:

• For notifications, resume is never called since there is no answer, so the request is never removed from the slab.
• For streams, an error is sent when the stream was dropped on crux side and so is never removed as well.

[charypar]

For notifications, we probably shouldn't put the reqests in the registry in the first place.

For streams the handling is harder - we need to confidently capture the situations when there's either no way the stream will produce another item (the external resolve handle has been dropped), or nobody is interested in the values any more (the stream was dropped) at which point we can drop them from the Slab.

Curious if this created a real-world problem @DeltaEvo? I'm aware of the potential for a kind of memory leak there, but couldn't think of a usage scenario which would lead to it actually reaching enough of a scale to be noticeable, so I left it for "when it becomes an issue in practice" 😅

For the record for passers by, this should be the only place in crux where that is the case.

[DeltaEvo]

I figured this out by reading the code, it wasn't found as the culprit of a out of memory issue, but since those are hard to debug I canno't be sure how much this contributed to the ones that we already encountered :/