[websocket] WebSocket subprotocol negotiation fails when using `Sec-WebSocket-Protocol` header

[A-kirami]

Describe the bug
When configuring the Sec-WebSocket-Protocol header in WebSocket connections using tauri-plugin-websocket, I encounter the error:
WebSocket protocol error: SubProtocol error: Server sent no subprotocol.

This occurs despite the same setup working correctly with Python's websockets library.

To Reproduce
Steps to reproduce the behavior:

1. Set up a simple WebSocket server (Python example provided below)
2. Attempt to connect using tauri-plugin-websocket with Sec-WebSocket-Protocol header
3. Observe the protocol error

Client code (TypeScript):

import WebSocket from '@tauri-apps/plugin-websocket';

const ws = await WebSocket.connect('ws://127.0.0.1:8080', {
  headers: {
    'Sec-WebSocket-Protocol': 'test'
  }
});

Server code (Python):

import asyncio
import websockets

async def echo(websocket):
    async for message in websocket:
        print(f"Received message: {message}")
        await websocket.send(f"Echo: {message}")

async def main():
    async with websockets.serve(echo, "localhost", port=8080):
        print("WebSocket server started, listening on port 8080...")
        await asyncio.Future()  # run forever

if __name__ == "__main__":
    asyncio.run(main())

Expected behavior
The connection should establish successfully when specifying Sec-WebSocket-Protocol, similar to how it works with Python's websockets library:

import asyncio
import websockets

async def ws(url, headers):
    async with websockets.connect(url, additional_headers=headers) as websocket:
        await websocket.send("Hello World!")
        # ... rest of implementation ...

custom_headers = {
    "Sec-WebSocket-Protocol": "test",
}

if __name__ == "__main__":
    asyncio.run(ws("ws://127.0.0.1:8080", headers=custom_headers))

Additional context

[✔] Environment
    - OS: Windows 10.0.26100 x86_64 (X64)
    ✔ WebView2: 136.0.3240.92
    ✔ MSVC: Visual Studio Community 2022
    ✔ rustc: 1.85.0-nightly (6b6a867ae 2024-11-27)
    ✔ cargo: 1.85.0-nightly (4c39aaff6 2024-11-25)
    ✔ rustup: 1.27.1 (54dd3d00f 2024-04-24)
    ✔ Rust toolchain: nightly-x86_64-pc-windows-msvc (default)
    - node: 23.5.0
    - pnpm: 9.14.2
    - npm: 10.9.2
    - bun: 1.2.12
    - deno: deno 2.1.4

[-] Packages
    - tauri 🦀: 2.5.1
    - tauri-build 🦀: 2.2.0
    - wry 🦀: 0.51.2
    - tao 🦀: 0.33.0
    - @tauri-apps/api : 2.5.0
    - @tauri-apps/cli : 2.5.0

[-] Plugins
    - tauri-plugin-websocket 🦀: 2.3.0
    - @tauri-apps/plugin-websocket : 2.3.0

[-] App
    - build-type: bundle
    - CSP: unset
    - frontendDist: ../dist
    - devUrl: http://localhost:1420/
    - bundler: Vite