[CI] Show disk usage for CI shared volume (#5821)

### What this PR does / why we need it?
1. Remove some useless but too large models from the shared volume
2. Add a new step to show current usage


- vLLM version: v0.13.0
- vLLM main:
2f4e6548ef

---------

Signed-off-by: wangli <wangli858794774@gmail.com>

.github/workflows/misc/model_list.json

@@ -25,8 +25,6 @@
       "LLM-Research/Llama-3.2-11B-Vision",
       "LLM-Research/Llama-3.2-1B-Instruct",
       "LLM-Research/Llama-3.2-3B-Instruct",
-      "LLM-Research/Llama-4-Scout-17B-16E-Instruct",
-      "LLM-Research/Llama-4-Scout-17B-16E-Instruct.",
       "LLM-Research/Meta-Llama-3-8B-Instruct",
       "LLM-Research/Meta-Llama-3.1-8B-Instruct",
       "LLM-Research/Molmo-7B-D-0924",
@@ -159,8 +157,6 @@
       "opendatalab/MinerU2.5-2509-1.2B",
       "rhymes-ai/Aria",
       "sentence-transformers/all-MiniLM-L12-v2",
-      "swift/Qwen3-235B-A22B-Instruct-2507-AWQ",
-      "tclf90/Qwen3-VL-235B-A22B-Instruct-AWQ",
       "tencent/HunyuanOCR",
       "unsloth/DeepSeek-V3.1-BF16",
       "unsloth/Kimi-K2-Thinking-BF16",