[BUG] offline tests fail

Botright should not depend on being online for tests wich do not require an internet connection

Example exception:

tests\test_playwright.py:95 (test_canvas_botright)
@pytest.mark.asyncio
    async def test_canvas_botright():
        botright_client = await botright.Botright(use_undetected_playwright=True, user_action_layer=True)
        try:
>           browser = await botright_client.new_browser(channel="chrome")

tests\test_playwright.py:100: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
.venv\lib\site-packages\botright\botright.py:147: in new_browser
    _proxy: ProxyManager = await ProxyManager(self, proxy)
.venv\lib\site-packages\async_class.py:173: in __await__
    yield from self.create_task(
.venv\lib\site-packages\botright\modules\proxy_manager.py:68: in __ainit__
    await self.check_proxy(self._phttpx)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

self = <botright.modules.proxy_manager.ProxyManager object at 0x00000245FA3CEE80>
httpx_client = <httpx.AsyncClient object at 0x00000245FA316B90>

    async def check_proxy(self, httpx_client: httpx.AsyncClient) -> None:
        """
        Check the validity of the proxy by making HTTP requests to determine its properties.
    
        Args:
            httpx_client (httpx.AsyncClient): The HTTPX client to use for proxy checks.
        """
        get_ip_apis = ["https://api.ipify.org/?format=json", "https://api.myip.com/", "https://get.geojs.io/v1/ip.json", "https://api.ip.sb/jsonip", "https://l2.io/ip.json"]
    
        for get_ip_api in get_ip_apis:
            try:
                ip_request = await httpx_client.get(get_ip_api, timeout=self.timeout)
                ip = ip_request.json().get("ip")
                break
            except Exception:
                pass
        else:
>           raise ProxyCheckError("Could not get IP-Address of Proxy (Proxy is Invalid/Timed Out)")
E           botright.modules.proxy_manager.ProxyCheckError: Could not get IP-Address of Proxy (Proxy is Invalid/Timed Out)

.venv\lib\site-packages\botright\modules\proxy_manager.py:123: ProxyCheckError

Start with tests/test_playwright.py, especially test_canvas_botright, and inspect the ProxyManager.check_proxy path shown in the traceback. Determine why this test performs external IP checks despite not requiring internet access. Done means offline tests that do not require networking no longer raise ProxyCheckError.