Fix units of sse_read_timeout timedelta (#1843)

Author: alexmojaki

pydantic_ai_slim/pydantic_ai/mcp.py

@@ -373,7 +373,7 @@ async def client_streams(
             url=self.url,
             headers=self.headers,
             timeout=timedelta(seconds=self.timeout),
-            sse_read_timeout=timedelta(self.sse_read_timeout),
+            sse_read_timeout=timedelta(seconds=self.sse_read_timeout),
         ) as (read_stream, write_stream, _):
             yield read_stream, write_stream