fix(mock-connection): use muxer to close/abort streams #3572

Job	Run time
Build	3m 7s
Test example js-libp2p-example-browser-pubsub	1m 48s
Test example js-libp2p-example-chat	55s
Test example js-libp2p-example-circuit-relay	1m 20s
Test example js-libp2p-example-connection-encryption	1m 13s
Test example js-libp2p-example-custom-protocols	55s
Test example js-libp2p-example-delegated-routing	2m 13s
Test example js-libp2p-example-discovery-mechanisms	1m 4s
Test example js-libp2p-example-peer-and-content-routing	1m 43s
Test example js-libp2p-example-pnet	51s
Test example js-libp2p-example-protocol-and-stream-muxing	54s
Test example js-libp2p-example-pubsub	1m 1s
Test example js-libp2p-example-transports	53s
Test example js-libp2p-example-webrtc-private-to-private	1m 44s
	19m 41s

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