fix: use publicKey.x instead of privateKey.x #3919

Job	Run time
Build	2m 56s
Test example js-libp2p-example-browser-pubsub	1m 51s
Test example js-libp2p-example-chat	59s
Test example js-libp2p-example-circuit-relay	1m 4s
Test example js-libp2p-example-connection-encryption	1m 3s
Test example js-libp2p-example-custom-protocols	1m 18s
Test example js-libp2p-example-delegated-routing	2m 30s
Test example js-libp2p-example-discovery-mechanisms	1m 9s
Test example js-libp2p-example-peer-and-content-routing	1m 47s
Test example js-libp2p-example-pnet	58s
Test example js-libp2p-example-protocol-and-stream-muxing	57s
Test example js-libp2p-example-pubsub	1m 40s
Test example js-libp2p-example-transports	1m 39s
Test example js-libp2p-example-webrtc-private-to-private	2m 15s
	22m 6s

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