all: update a few more references to network/tailnet lock

Updates tailscale/corp#37904

Change-Id: I746b06328e080fa2b9ff28a2d099f95645aa3d0b
Signed-off-by: Alex Chan <alexc@tailscale.com>

tstest/integration/integration.go

@@ -1130,7 +1130,7 @@ func (n *TestNode) PublicKey() string {
 	return st.Self.PublicKey
 }
 
-// NLPublicKey returns the hex-encoded network lock public key of
+// NLPublicKey returns the hex-encoded tailnet lock public key of
 // this node, e.g. `tlpub:123456abc`
 func (n *TestNode) NLPublicKey() string {
 	tb := n.env.t