【bugfix】fix connector register failed (#3335)

### What this PR does / why we need it?
Register the connector in the plugin
### Does this PR introduce _any_ user-facing change?

### How was this patch tested?


- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

---------

Signed-off-by: fems14 <1804143737@qq.com>

vllm_ascend/__init__.py

@@ -27,3 +27,8 @@ def register_model():
 
     from .models import register_model
     register_model()
+
+
+def register_connector():
+    from vllm_ascend.distributed import register_connector
+    register_connector()