fix: add pragma no branch for coverage on pytest.raises

Author: vishal-vanam

tests/shared/test_streamable_http.py

@@ -2334,5 +2334,5 @@ def return_plain_text(request: httpx.Request) -> httpx.Response:
         write_stream,
     ):
         async with ClientSession(read_stream, write_stream) as session:
-            with pytest.raises(MCPError, match="Unexpected content type"):
+            with pytest.raises(MCPError, match="Unexpected content type"):  # pragma: no branch
                 await session.initialize()