chore: close px connections after resp

[alrevuelta]

• Since peer exchange protocol is req/resp and after exchanging the req/resp it's not very likely that the stream will be reused, we shall close the stream.
• Note that .closeWithEOF() is used instead of .close() see.
• A test is added that will fail without the changes introduced in this PR.
• Note that the stream is closed but not the connection.

[jm-clius]

Thanks! And good catch. Should we do the same for other req/resp protocols?

[alrevuelta]

Should we do the same for other req/resp protocols?

@jm-clius I would lightpush for sure and perhaps also store?

But unsure given:

I imagine the expected behaviour would be to close streams for "pure" req/resp protocols after every resp and to keep it open if there's a high likelihood for follow-up requests (e.g. filter push, subsequent store queries, etc.)