WebSocketClientHandshaker: add public accessors for parameters (#13009)

Motivation:

Websocket client & server handshakers may be extended with custom frame encoder / decoder,
however client handshaker parameters are private so cant be accessed by custom frame encoder / decoder.

Modifications:

WebSocketClientHandshaker: add public accessors for parameters.

Result:

Custom frame encoder / decoder may be provided with websocket client handshaker parameters

codec-http/src/main/java/io/netty5/handler/codec/http/websocketx/WebSocketClientHandshaker13.java

@@ -167,8 +167,6 @@ public WebSocketClientHandshaker13(URI webSocketURL, String subprotocol,
      * @param webSocketURL
      *            URL for web socket communications. e.g "ws://myhost.com/mypath". Subsequent web socket frames will be
      *            sent to this URL.
-     * @param version
-     *            Version of web socket specification to use to connect to the server
      * @param subprotocol
      *            Sub protocol request sent to the server.
      * @param allowExtensions
@@ -331,4 +329,16 @@ private static String createNonce() {
         var nonce = WebSocketUtil.randomBytes(16);
         return WebSocketUtil.base64(nonce);
     }
+
+    public boolean isAllowExtensions() {
+        return allowExtensions;
+    }
+
+    public boolean isPerformMasking() {
+        return performMasking;
+    }
+
+    public boolean isAllowMaskMismatch() {
+        return allowMaskMismatch;
+    }
 }