Bug: `K3SContainer` does not support other connection modes (in `get_container_host_ip`)

Describe the bug

K3SContainer calls get_container_host_ip in its __init__ method here and here before the container is started, causing it to fail with an AssertionError here.

To Reproduce

from testcontainers.k3s import K3SContainer

with K3SContainer() as k3s:
     print("gonna throw an error before I even get here :(")

Runtime environment

I'm on an ARM Mac and this is in Python 3.12, but that shouldn't make a difference.

从 modules/k3s/testcontainers/k3s/init.py 中 K3SContainer.init 调用 get_container_host_ip 的位置开始，然后检查 core/testcontainers/core/container.py 中 assertion 附近的代码。复现提供的 K3SContainer 上下文管理器示例，并验证初始化在 startup 之前不再失败，且其他连接模式也受支持。