[Misc][V0 Deprecation] Remove Pooling Model Runner (#1824)

### What this PR does / why we need it?
Remove pooling model runner.

This PR is a part of
#1620.

- vLLM version: v0.9.2
- vLLM main:
vllm-project/vllm@d31a647

Signed-off-by: shen-shanshan <467638484@qq.com>

Author: shen-shanshan