test(teams): consolidate duplicate certificate-auth validation test

Addresses bot review feedback on PR #65 — the same startup-throw check
existed in both test_teams_coverage.py and test_teams_extended.py. Kept
the detailed version, removed the duplicate.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: patrick-chinchill

tests/test_teams_coverage.py

@@ -29,7 +29,6 @@
 )
 from chat_sdk.adapters.teams.types import (
     TeamsAdapterConfig,
-    TeamsAuthCertificate,
     TeamsThreadId,
 )
 from chat_sdk.shared.errors import (
@@ -1482,26 +1481,6 @@ def routed_post(url, **kwargs):
             assert len(result.messages) >= 0
 
 
-# ---------------------------------------------------------------------------
-# Certificate config raises
-# ---------------------------------------------------------------------------
-
-
-class TestCertificateConfig:
-    def test_certificate_raises_validation_error(self):
-        with pytest.raises(ValidationError, match="Certificate"):
-            TeamsAdapter(
-                TeamsAdapterConfig(
-                    app_id="test",
-                    app_password="test",
-                    certificate=TeamsAuthCertificate(
-                        certificate_private_key="key",
-                        certificate_thumbprint="abc",
-                    ),
-                )
-            )
-
-
 # ---------------------------------------------------------------------------
 # _extract_attachments_from_graph_message
 # ---------------------------------------------------------------------------