Fix off-by-one/memory corruption in transport_ws

Read doesn't take NULL terminator into account

Resolves #14473

components/tcp_transport/transport_ws.c

@@ -285,7 +285,7 @@ static int ws_connect(esp_transport_handle_t t, const char *host, int port, int
     }
     int header_len = 0;
     do {
-        if ((len = esp_transport_read(ws->parent, ws->buffer + header_len, WS_BUFFER_SIZE - header_len, timeout_ms)) <= 0) {
+        if ((len = esp_transport_read(ws->parent, ws->buffer + header_len, WS_BUFFER_SIZE - header_len - 1, timeout_ms)) <= 0) {
             ESP_LOGE(TAG, "Error read response for Upgrade header %s", ws->buffer);
             return -1;
         }