Simplify get pipeline method (#93865)

homeassistant/components/assist_pipeline/websocket_api.py

@@ -17,6 +17,7 @@ from homeassistant.helpers import config_validation as cv
 from homeassistant.util import language as language_util
 
 from .const import DOMAIN
+from .error import PipelineNotFound
 from .pipeline import (
     PipelineData,
     PipelineError,
@@ -85,8 +86,9 @@ async def websocket_run(
 ) -> None:
     """Run a pipeline."""
     pipeline_id = msg.get("pipeline")
-    pipeline = async_get_pipeline(hass, pipeline_id=pipeline_id)
-    if pipeline is None:
+    try:
+        pipeline = async_get_pipeline(hass, pipeline_id=pipeline_id)
+    except PipelineNotFound:
         connection.send_error(
             msg["id"],
             "pipeline-not-found",