fix: remove unused anyio import and unnecessary pragma: no cover annotations

Author: RJ Lopez

src/mcp/client/session_group.py

@@ -13,7 +13,6 @@
 from types import TracebackType
 from typing import Any, TypeAlias
 
-import anyio
 import httpx
 from pydantic import BaseModel, Field
 from typing_extensions import Self

tests/server/test_streamable_http_manager.py

@@ -119,7 +119,7 @@ async def mock_send(message: Message):
         "headers": [(b"content-type", b"application/json")],
     }
 
-    async def mock_receive():  # pragma: no cover
+    async def mock_receive():
         return {"type": "http.request", "body": b"", "more_body": False}
 
     # Trigger session creation
@@ -178,7 +178,7 @@ async def mock_send(message: Message):
         "headers": [(b"content-type", b"application/json")],
     }
 
-    async def mock_receive():  # pragma: no cover
+    async def mock_receive():
         return {"type": "http.request", "body": b"", "more_body": False}
 
     # Trigger session creation
@@ -357,7 +357,7 @@ async def mock_send(message: Message):
             "headers": [(b"content-type", b"application/json")],
         }
 
-        async def mock_receive():  # pragma: no cover
+        async def mock_receive():
             return {"type": "http.request", "body": b"", "more_body": False}
 
         await manager.handle_request(scope, mock_receive, mock_send)