coverage85-step2d: 新测试 lint 清理（删无用导入与变量）

cloud/tests/test_coverage85_server2.py

@@ -304,7 +304,6 @@ class Server2TestCase(unittest.TestCase):
         self.assertEqual(status, 400)
 
     def test_create_task_valid_variants(self):
-        pid = self.project["id"]
         task = self._create_task(self.owner_key, depends_on="dep-1")
         self.assertEqual(task["depends_on"], ["dep-1"])
         task = self._create_task(self.owner_key, prompt="/goal 收邮件")