Elastic-package Prevents Reusing Saved Navigation Link Panels Across Dashboards

**Description:**

I encountered an issue where **elastic-package** is preventing the use of saved navigation link panels across multiple dashboards.

I created link panels and saved them to the library with the intention of reusing them across different dashboards, similar to how saved searches work. However, when I attempted to reuse these saved link panels in a [PR](https://github.com/elastic/integrations/pull/15344/commits/c45982db9c067c4bbd7c4a4e3506cf07b9fd2ac8), the build and check commands failed.

During the import process, the navigation link panels are saved into a `link `folder, but when running the elastic-package command, it throws an error stating that the link folder is not allowed.

This seems to be a limitation in elastic-package, as ideally, it should support reusing navigation link panels to avoid duplication and improve maintainability.

**Steps to Reproduce:**

- Create a navigation link panel and save it to the library.
- Try reusing the saved navigation panel in multiple dashboards.
- Export the dashboards
- Run the elastic-package check or build command.
- Observe the error indicating that the link folder is not allowed.

**Expected Behavior:**

The elastic-package should allow saving and reusing navigation link panels across dashboards without throwing errors.

**Actual Behavior:**

The package fails validation and throws an error when it detects a link folder created as part of saving navigation panels.
_Error-_
```
Lint the package
Error: checking package failed: linting package failed: found 1 validation error:
1. item [link] is not allowed in folder [/root/github_integrations/integrations/packages/ti_abusech/kibana]
```

**Additional Context:**

This feature would be highly valuable, as reusing saved navigation panels across dashboards should be supported and not restricted.

Start with the elastic-package check and build validation that rejects the link folder under a package's kibana directory. Reproduce the failure using the dashboard export and package path described in the issue, then identify the validation tests covering allowed Kibana items. Done means navigation link panels can be reused and both commands pass without the link-folder error.

Written by the indexing model from the issue text.