CI: Replace nightly image build with S3 aiter wheel installation #1480

Job	Run time
pre-checks / Check Code Style with Ruff	11s
pre-checks / Check Code Style with Black	12s
ATOM Test (Llama-3.3-70B-Instruct-MXFP4-Preview, amd/Llama-3.3-70B-Instruct-MXFP4-Preview, --kv_c...	35m 18s
ATOM Test (DeepSeek-R1-0528, deepseek-ai/DeepSeek-R1-0528, --kv_cache_dtype fp8 -tp 8, 0.94, atom...	11m 43s
ATOM Test (DeepSeek-R1-0528-FP4 MTP, amd/DeepSeek-R1-0528-MXFP4, --kv_cache_dtype fp8 -tp 8 --met...	13m 27s
ATOM Test (Qwen3-235B-A22B-Instruct-2507-FP8, Qwen/Qwen3-235B-A22B-Instruct-2507-FP8, --kv_cache_...	8m 51s
ATOM Test (Meta-Llama-3-8B-Instruct, meta-llama/Meta-Llama-3-8B-Instruct, --kv_cache_dtype fp8 --...	38m 51s
ATOM Test (gpt-oss-120b (2 GPUs), openai/gpt-oss-120b, --kv_cache_dtype fp8 -tp 2 --enable-dp-att...	47m 27s
ATOM Test (gpt-oss-120b, openai/gpt-oss-120b, --kv_cache_dtype fp8 --gpu-memory-utilization 0.3, ...	37m 26s
ATOM Test (DeepSeek-R1-0528 MTP, deepseek-ai/DeepSeek-R1-0528, --kv_cache_dtype fp8 -tp 8 --metho...	14m 31s
ATOM Test (Qwen3-235B-A22B-Instruct-2507-MXFP4, amd/Qwen3-235B-A22B-Instruct-2507-MXFP4, --kv_cac...	15s
ATOM Test (DeepSeek-R1-0528-FP4, amd/DeepSeek-R1-0528-MXFP4, --kv_cache_dtype fp8 -tp 8, 0.93, at...	14m 49s
ATOM Test (Qwen3-Next-80B-A3B-Thinking, Qwen/Qwen3-Next-80B-A3B-Thinking, -tp 8, 0.65, atom-mi355...	9m 41s
	3h 52m 42s

Provide feedback