[Doc] Add qwen3 embedding 8b guide (#1734)

1. Add the tutorials for qwen3-embedding-8b
2. Remove VLLM_USE_V1=1  in docs, it's useless any more from 0.9.2


- vLLM version: v0.9.2
- vLLM main:
5923ab9524

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

docs/source/tutorials/single_node_300i.md

@@ -60,7 +60,6 @@ Run the following command to start the vLLM server:
 
 ```{code-block} bash
    :substitutions:
-export VLLM_USE_V1=1
 vllm serve Qwen/Qwen3-0.6B \
     --tensor-parallel-size 1 \
     --enforce-eager \
@@ -90,7 +89,6 @@ Run the following command to start the vLLM server:
 
 ```{code-block} bash
    :substitutions:
-export VLLM_USE_V1=1
 vllm serve Qwen/Qwen2.5-7B-Instruct \
     --tensor-parallel-size 2 \
     --enforce-eager \
@@ -129,7 +127,7 @@ Run the following command to start the vLLM server:
 ```{code-block} bash
    :substitutions:
 
-VLLM_USE_V1=1 vllm serve /home/pangu-pro-moe-mode/ \
+vllm serve /home/pangu-pro-moe-mode/ \
 --tensor-parallel-size 4 \
 --enable-expert-parallel \
 --dtype "float16" \
@@ -321,7 +319,7 @@ if __name__ == "__main__":
 
 Run script:
 ```bash
-VLLM_USE_V1=1 python example.py
+python example.py
 ```
 
 If you run this script successfully, you can see the info shown below: