Skip OTel test when logfire.testing is not available

The lowest-direct CI resolution may not install a logfire version
that includes the testing module.

Author: Kludex

tests/shared/test_otel.py

@@ -1,10 +1,12 @@
 from __future__ import annotations
 
 import pytest
-from logfire.testing import CaptureLogfire
 
-from mcp.client.client import Client
-from mcp.server.mcpserver import MCPServer
+logfire_testing = pytest.importorskip("logfire.testing")
+CaptureLogfire = logfire_testing.CaptureLogfire
+
+from mcp.client.client import Client  # noqa: E402
+from mcp.server.mcpserver import MCPServer  # noqa: E402
 
 pytestmark = pytest.mark.anyio