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)



<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## 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.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

web/src/services/next-chat-service.ts

@@ -16,10 +16,6 @@ const {
   removeSessions,
   deleteMessage,
   thumbup,
-  createToken,
-  listToken,
-  removeToken,
-  getStats,
   chatsTts,
   ask,
   chatsMindmap,
@@ -85,22 +81,6 @@ const methods = {
     url: thumbup,
     method: 'put',
   },
-  createToken: {
-    url: createToken,
-    method: 'post',
-  },
-  listToken: {
-    url: listToken,
-    method: 'get',
-  },
-  removeToken: {
-    url: removeToken,
-    method: 'post',
-  },
-  getStats: {
-    url: getStats,
-    method: 'get',
-  },
   chatsTts: {
     url: chatsTts,
     method: 'post',