### What this PR does / why we need it?
1. Enable tests/e2e/multicard/test_external_launcher.py
2. Add e2e test for sleep mode in level2
### Does this PR introduce _any_ user-facing change?
not involved
### How was this patch tested?
CI passed with existing test.
- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0
Signed-off-by: huangxialu <huangxialu1@huawei.com>
Co-authored-by: Shangwei-Li <lishangwei2@huawei.com>