Refactor: Remove unused API code (#13978)

### What problem does this PR solve?

Refactor: Remove unused API code

### Type of change


- [x] New Feature (non-breaking change which adds functionality)



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## Summary by CodeRabbit

* **Style**
* Updated table header styling in dataset settings by removing a
hard-coded background color class, allowing the header to use default or
inherited component styling instead.

* **Refactor**
* Removed token management endpoints from the API service. Token
creation, listing, and removal functions are no longer available.
  * Removed the statistics data endpoint from available API routes.

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