Refa: Move HTTP API tests to top-level test directory (#8042)

### What problem does this PR solve?

Move test cases only - CI still runs tests under sdk/python

### Type of change

- [x] Refactoring

test/testcases/test_http_api/test_dataset_mangement/conftest.py

@@ -0,0 +1,39 @@
+#
+#  Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+
+import pytest
+from common import batch_create_datasets, delete_datasets
+
+
+@pytest.fixture(scope="class")
+def add_datasets(api_key, request):
+    def cleanup():
+        delete_datasets(api_key, {"ids": None})
+
+    request.addfinalizer(cleanup)
+
+    return batch_create_datasets(api_key, 5)
+
+
+@pytest.fixture(scope="function")
+def add_datasets_func(api_key, request):
+    def cleanup():
+        delete_datasets(api_key, {"ids": None})
+
+    request.addfinalizer(cleanup)
+
+    return batch_create_datasets(api_key, 3)