Xray-core: Forbid unencrypted outbounds on public Internet for VLESS and Trojan; Remove "none/zero/plain" for VMess and Shadowsocks (#6303)

https://github.com/XTLS/Xray-core/pull/5640#issuecomment-4611416512
https://github.com/XTLS/Xray-core/pull/6303#issuecomment-4668055274

---------

Co-authored-by: Meow <197331664+Meo597@users.noreply.github.com>

proxy/shadowsocks/protocol_test.go

@@ -38,19 +38,6 @@ func TestUDPEncodingDecoding(t *testing.T) {
 				}),
 			},
 		},
-		{
-			Version: Version,
-			Command: protocol.RequestCommandUDP,
-			Address: net.LocalHostIP,
-			Port:    1234,
-			User: &protocol.MemoryUser{
-				Email: "love@example.com",
-				Account: toAccount(&Account{
-					Password:   "123",
-					CipherType: CipherType_NONE,
-				}),
-			},
-		},
 	}
 
 	for _, request := range testRequests {
@@ -80,10 +67,6 @@ func TestUDPDecodingWithPayloadTooShort(t *testing.T) {
 			Password:   "password",
 			CipherType: CipherType_AES_128_GCM,
 		}),
-		toAccount(&Account{
-			Password:   "password",
-			CipherType: CipherType_NONE,
-		}),
 	}
 
 	for _, account := range testAccounts {