fix: update getting help (#846)

## Summary by Sourcery

Revise the ‘Need help?’ section in the documentation by removing
obsolete links and updating the demo scheduling URL

Documentation:
- Remove Discord community and SettleMint Academy training links from
the ‘Need help?’ section
- Update the Demo link to point to the new booking page on
settleMint.com



<!-- This is an auto-generated description by cubic. -->
---
## Summary by cubic
Updated the “Need help?” section on the docs index to use the current
Demo and Academy URLs and remove the Discord link. This fixes outdated
links and directs users to the correct booking and training pages.

<sup>Written for commit bb75551.
Summary will update automatically on new commits.</sup>

<!-- End of auto-generated description by cubic. -->



<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> Updates the “Need help?” section: removes Discord link and updates
Demo and Academy URLs.
> 
> - **Docs**:
>   - **`content/docs/index.mdx`**:
>     - Remove `Community` (Discord) link from “Need help?”
> - Update `Demo` link to
`https://www.settlemint.com/select-region-book-a-call`
> - Update `Training` (Academy) link to `https://learn.settlemint.com/`
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
94cd13d. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Co-authored-by: Roderik van der Veer <roderik@settlemint.com>

Author: SaeeDawod

content/docs/index.mdx

@@ -816,6 +816,5 @@ SettleMint Application Kits provide complete, full-stack blockchain solutions fo
 ## Need help?
 
 - 📧 **Support:** [support@settlemint.com](mailto:support@settlemint.com)
-- 💬 **Community:** [Join our Discord](https://discord.gg/settlemint)
-- 📅 **Demo:** [Schedule a call](https://settlemint.com/demo)
-- 🎓 **Training:** [SettleMint Academy](https://academy.settlemint.com)
+- 📅 **Demo:** [Schedule a call](https://www.settlemint.com/select-region-book-a-call)
+- 🎓 **Training:** [SettleMint Academy](https://learn.settlemint.com/)