[bug]: Params not sent to the server correctly in websocket playground

[ccavolt]

Describe the bug
Params aren't sent to the server properly.

To Reproduce
In the websocket playground I use the following URL:

ws://localhost:4000/socket/websocket?vsn=2.0.0

When I send the request via Postman (or Insomnia/Hoppscotch), vsn=2.0.0 is received by the server and I get the following response:

Transport: :websocket
Serializer: Phoenix.Socket.V2.JSONSerializer
Parameters: %{"vsn" => "2.0.0"}

When I send the request via Firecamp, I get the following response:

Transport: :websocket
Serializer: Phoenix.Socket.V1.JSONSerializer
Parameters: %{}

Which indicates the params either didn't make it to the server or are malformed.

Expected behavior
The server will receive the params.

Desktop (please complete the following information):

• OS: Browser is Windows, server is running Ubuntu 22.04.4 LTS
• Browser: Chrome
• Version: 125.0.6422.142