feat(FR-1421): enhance WEBUI help button with additional page mappings (#4212)

Resolves #4211 ([FR-1421](https://lablup.atlassian.net/browse/FR-1421))

# Add help button links for new pages

This PR adds help button links for several pages:
- `session` page now links to sessions_all documentation
- `chat` page now links to chat documentation
- `agent-summary` page now links to agent_summary documentation
- `resource-policy` page now links to the resource policy section in admin menu documentation

Additionally, removed the `service` page link as it's no longer needed.

**Checklist:**
- [ ] Documentation
- [ ] Minium required manager version
- [ ] Specific setting for review (eg., KB link, endpoint or how to setup)
- [ ] Minimum requirements to check during review
- [ ] Test case(s) to demonstrate the difference of before/after

[FR-1421]: https://lablup.atlassian.net/browse/FR-1421?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ

Author: agatha197

react/src/components/WEBUIHelpButton.tsx

@@ -14,13 +14,16 @@ const WEBUIHelpButton: React.FC<WEBUIHelpButtonProps> = ({ ...props }) => {
     '': 'summary/summary.html',
     summary: 'summary/summary.html',
     job: 'sessions_all/sessions_all.html',
+    session: 'sessions_all/sessions_all.html',
+    chat: 'chat/chat.html',
     serving: 'model_serving/model_serving.html',
-    service: 'model_serving/model_serving.html',
     import: 'import_run/import_run.html',
     data: 'vfolder/vfolder.html',
+    'agent-summary': 'agent_summary/agent_summary.html',
     statistics: 'statistics/statistics.html',
     credential: 'admin_menu/admin_menu.html',
     environment: 'admin_menu/admin_menu.html#manage-images',
+    'resource-policy': 'admin_menu/admin_menu.html#manage-resource-policy',
     agent: 'admin_menu/admin_menu.html#query-agent-nodes',
     settings: 'admin_menu/admin_menu.html#system-settings',
     maintenance: 'admin_menu/admin_menu.html#server-management',