control/controlclient: avoid Noise protocol for js/wasm for now

Updates #3157

Change-Id: I04accc09783a68257d28cadde5818bf0724a8013
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

control/controlclient/direct.go

@@ -1097,6 +1097,12 @@ func loadServerPubKeys(ctx context.Context, httpc *http.Client, serverURL string
 	var out tailcfg.OverTLSPublicKeyResponse
 	jsonErr := json.Unmarshal(b, &out)
 	if jsonErr == nil {
+		if runtime.GOOS == "js" {
+			// As of 2022-05-20 it's not possible for js/wasm to make a bidi
+			// Noise connection to the control plane. Instead, for now, pretend
+			// like the server can't do Noise to force use of the old protocol.
+			out.PublicKey = key.MachinePublic{}
+		}
 		return &out, nil
 	}