test(scheduler): 移除对 clear_cache provider_name 的冗余断言

该字段未被实现显式设置，测试应仅校验 clear_cache 的 manual 语义。

Co-Authored-By: CodeBuddy Code <hy3@tencent.com>

tests/test_scheduler_cache_expiry.py

@@ -101,5 +101,4 @@ def test_clear_cache_is_manual_only(monkeypatch):
     assert "clear_cache" not in scheduled_job_ids
     assert "clear_cache" in scheduler._jobs
     assert scheduler._jobs["clear_cache"]["manual"] is True
-    assert scheduler._jobs["clear_cache"]["provider_name"] == "[系统]"
     assert background_scheduler.started is True