### What this PR does / why we need it?
Rectify the problem that the pcp and pd separation and kv pooling
scenario.
In the pooling scenario, multi_nodes_meta_mapping is empty. As a result,
an error is reported when the remote_host information is obtained
through the get_remote_port_send_num method.
### Does this PR introduce _any_ user-facing change?
No
- vLLM version: v0.13.0
- vLLM main:
d68209402d
Signed-off-by: weiguihua2 <weiguihua2@huawei.com>
4173255c0c