GraphQL timeout error when loading Secrets Manager user permissions
### Summary
The Secrets Manager user permissions list fails to load due to a request timeout error from the permissions endpoint.
### Steps to reproduce
1. Enable Secrets Manager for a Project from Settings
2. Navigate to the Secrets Manager permissions section
3. Observe the timeout error when trying to load the user permissions list
### What is the current *bug* behavior?
A timeout error occurs when attempting to load the Secrets Manager user permissions list. This error is not visible in the GitLab UI - it silently fails.
### What is the expected *correct* behavior?
The Secrets Manager user permissions list should load successfully.
### Relevant logs and/or screenshots
**Screenshot:**
{width=773 height=133}
<details>
<summary>Request and Response</summary>
**Request Payload:**
```json
{
"operationName": "secretPermissions",
"variables": {
"projectPath": "issue-reproduce/gitlab-secrets-manager-group/project-secrets"
},
"query": "query secretPermissions($projectPath: ID!) {\n projectSecretsPermissions(projectPath: $projectPath) {\n nodes {\n expiredAt\n grantedBy {\n id\n username\n name\n avatarUrl\n webUrl\n __typename\n }\n actions\n principal {\n id\n type\n userRoleId\n user {\n id\n username\n name\n avatarUrl\n webUrl\n __typename\n }\n group {\n id\n name\n avatarUrl\n webUrl\n __typename\n }\n __typename\n }\n project {\n id\n __typename\n }\n __typename\n }\n __typename\n }\n}"
}
```
**Response:**
```json
{
"errors": [
{
"message": "Request timed out. Please try a less complex query or a smaller set of records."
}
]
}
```
</details>
More details: https://gitlab.com/gitlab-org/gitlab/-/issues/554928#note_2691590521
### Possible fixes
- **Batch loading** - This was implemented in https://gitlab.com/gitlab-org/gitlab/-/merge_requests/202493+ but did not work. See https://gitlab.com/gitlab-org/gitlab/-/work_items/562240#note_2807185438
- **Use new endpoint introduced in OpenBao 2.5.0** - This is covered by https://gitlab.com/gitlab-org/gitlab/-/work_items/585567+.
### Patch release information for backports
If the bug fix needs to be backported in a [patch release](https://handbook.gitlab.com/handbook/engineering/releases/patch-releases) to a version under [the maintenance policy](https://docs.gitlab.com/policy/maintenance/), please follow the steps on the [patch release runbook for GitLab engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/patch/engineers.md).
Refer to the [internal "Release Information" dashboard](https://dashboards.gitlab.net/d/delivery-release_info/delivery3a-release-information?orgId=1) for information about the next patch release, including the targeted versions, expected release date, and current status.
#### High-severity bug remediation
To remediate high-severity issues requiring an [internal release](https://handbook.gitlab.com/handbook/engineering/releases/internal-releases/) for single-tenant SaaS instances, refer to the [internal release process for engineers](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/internal-releases/engineers.md?ref_type=heads).
issue