fix: font size in Join a Partner page (#56)

Fixes: 
<img width="2032" alt="image"
src="https://github.com/user-attachments/assets/b403cda7-52fc-408a-a8fb-2556bfd732a6">

Fixed:

<img width="2032" alt="image"
src="https://github.com/user-attachments/assets/a7a96e0e-63b7-4951-ba3b-720a78f697fc">


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

## Summary by CodeRabbit

- **New Features**
- Updated billing and invoicing documentation to clarify that partner
organizations will now handle all invoicing for resource usage on
SettleMint.
- Removed previous mentions of direct invoicing from SettleMint to
organizations, streamlining the billing process.
- Eliminated the final invoice reference for the latest payment period
to simplify financial interactions.

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

Author: snigdha920

docs/account-billing/join-a-partner.mdx

@@ -34,18 +34,11 @@ In this case, these costs are now managed by the partner's organization.
 
 Depending on your configuration, the invoicing for your resource usage can either be handled by the partner or directly with SettleMint.
 If handled by the partner, the billing changes will take effect in the same billing cycle when the transfer is made.
-=======
 
 ### Resource Cost Monitoring
 
 The cost of resources your organization uses on SettleMint (ex: Blockchain Networks/Nodes) will no longer be shown. This will be handled by the partner.
 
-### Billing
-
-Your organization will no longer receive invoices directly from SettleMint for the cost of your organization's resource usage. Billing and Invoicing will be handled through your assigned partner.
-
-There will be a final invoice sent to your organization for the latest payment period before linking your account to a partner.
-
 ## How to join a partner
 
 1. **Open Organizations & Apps**