test(services/cos): skip create-dir list checks that require strong list consistency

## Problem

`behavior::test_list_sub_dir` can fail for COS after creating a directory marker and immediately listing the bucket root:

```text
dir should be found in list
```

OpenDAL simulates `create_dir` for COS by writing an empty object at `/`. The test then immediately calls `list("/")` and expects the new directory marker to be returned.

## Root cause

Tencent COS documents that GET Bucket / List Objects is eventually consistent after uploads. If an object is uploaded and GET Bucket is called immediately, the returned result may not include the newly uploaded object.

Reference: https://www.tencentcloud.com/document/product/436/30614/

## Expected handling

Behavior tests that require immediate read-after-write visibility through COS ListObjects should be skipped for COS, because the service contract does not provide the required strong list consistency.

Start with the behavior::test_list_sub_dir behavior test and the COS service test setup. Run the relevant behavior tests to reproduce the immediate listing failure, then verify that list-consistency checks are skipped for COS while remaining enabled for services with strong consistency.

Written by the indexing model from the issue text.