[Doc] add tls check to pd disaggregation readme (#5638)

### What this PR does / why we need it?

update pd disaggregation multi_node readme, update the environment check
command for A3, add tls check
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?


- vLLM version: v0.13.0
- vLLM main:
8be6432bda

Signed-off-by: liziyu <liziyu16@huawei.com>

docs/source/tutorials/pd_colocated_mooncake_multi_instance.md

@@ -44,7 +44,7 @@ such as IP addresses according to your actual environment.
    for i in {0..7}; do hccn_tool -i $i -gateway -g ; done
    ```
 
-2. Check NPU Network Configuration:
+2. Check NPU HCCN Configuration:
 
    Ensure that the hccn.conf file exists in the environment. If using Docker,
    mount it into the container.
@@ -67,6 +67,13 @@ such as IP addresses according to your actual environment.
    for i in {0..7}; do hccn_tool -i $i -ping -g address x.x.x.x; done
    ```
 
+5. Check NPU TLS Configuration
+
+   ```bash
+   # The tls settings should be consistent across all nodes
+   for i in {0..7}; do hccn_tool -i $i -tls -g ; done | grep switch
+   ```
+
 ## Run with Docker
 
 Start a Docker container on each node.