### Check for existing issues

- [x] I have searched the existing issues and checked that my issue is not a duplicate.

### What happened?

When the `llm_requests_hanging` Slack alert fires, the **Key Alias** and **Team Alias** fields are always blank, regardless of which key/team made the request. This makes the alert unable to identify who is responsible for the hang.

**Expected:** the alert shows the key/team alias of the hanging request. **Actual:** `Key Alias` and `Team Alias` are always empty.

**Root cause (on `litellm_internal_staging`):**

`AlertingHangingRequestCheck.add_request_to_hanging_request_check` reads request metadata via `get_litellm_metadata_from_kwargs()`:

- `litellm/integrations/SlackAlerting/hanging_request_check.py:60`

```python request_metadata = get_litellm_metadata_from_kwargs(kwargs=request_data) ```

- `litellm/integrations/SlackAlerting/hanging_request_check.py:74-75`

```python key_alias=request_metadata.get("user_api_key_alias", ""), team_alias=request_metadata.get("user_api_key_team_alias", ""), ```

- `litellm/litellm_core_utils/core_helpers.py:169` — `get_litellm_metadata_from_kwargs` reads **only** `kwargs["litellm_params"]["met…