Blackhole outbound: Add customizable response data support (#6713)

https://github.com/XTLS/Xray-core/pull/6711#issuecomment-5508683394

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Co-authored-by: Raaad1on <djilyawhite@gmail.com>

proxy/blackhole/config.proto

@@ -6,12 +6,11 @@ option go_package = "github.com/xtls/xray-core/proxy/blackhole";
 option java_package = "com.xray.proxy.blackhole";
 option java_multiple_files = true;
 
-import "common/serial/typed_message.proto";
-
-message NoneResponse {}
-
-message HTTPResponse {}
+message Response {
+  string type = 1;
+  bytes custom_response_data = 2;
+}
 
 message Config {
-  xray.common.serial.TypedMessage response = 1;
+  Response response = 1;
 }