[Docs] UB (#7333)

CORE-0000

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## PR-Codex overview
This PR focuses on enhancing the documentation for the `Universal Bridge` by adding troubleshooting information and FAQs regarding payment issues and token support.

### Detailed summary
- Added a section for handling "Error 500: Internal Server Error" with upgrade instructions for the SDK.
- Included a new FAQ on supporting tokens on the `Universal Bridge` with criteria and request instructions.

> ✨ Ask PR-Codex anything about this PR by commenting with `/codex {your question}`

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

## Summary by CodeRabbit

- **Documentation**
  - Added a new FAQ explaining how to request support for a token on Universal Bridge, including submission steps and expected processing time.
  - Introduced troubleshooting guidance for resolving "Error 500" or "Something went wrong" messages in Universal Bridge, with instructions to update the SDK and contact support if needed.

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

Author: saminacodes

apps/portal/src/app/pay/faqs/page.mdx

@@ -29,6 +29,17 @@ This can include intents, native bridges, third party bridges, cross-chain messa
 health, price, and speed to guarantee the best path every time. 
 </Details>
 
+<Details summary="How can I support a token on Universal Bridge?"> 
+Universal Bridge is able to support most token that meet the following criteria:
+
+- The token must have sufficient liquidity
+- The token must be on a [supported Universal Bridge Chain](https://thirdweb.com/chainlist?service=pay).
+
+To request support for a token, please visit the Universal Bridge tab in your project dashboard > Settings > "Don't see your token listed?" component and fill out the chain and token address information.
+
+Universal Bridge will automatically kick off the token route discovery process. Please check back the Universal Bridge modal after 20-40 minutes for the requested token. 
+</Details>
+
 <Details summary="Am I able to use Universal Bridge with other wallet infrastructure providers?"> 
 Yes, Universal Bridge is designed to be agnostic to wallet infrastructure. You can use it with any wallet service. 
 </Details>

apps/portal/src/app/pay/troubleshoot/page.mdx

@@ -8,4 +8,13 @@ When using onramp providers, you may encounter an error stating "There was an is
 This typically means that your card issuer does not allow cryptocurrency purchases.
 
 To work around this issue, you can try using a different card or payment method, such as debit card, if available.
+</Details>
+
+<Details summary="Error 500: Internal Server Error">
+If you encounter an "Error 500: Internal Server Error" or if the modal shows "Something went wrong" it may indicate you are using an
+outdated version of the Universal Bridge service. 
+
+To resolve this issue, please upgrade your SDK to the latest version in your project. You can download the latest version with `npm install thirdweb@latest` or `yarn add thirdweb@latest`.
+
+If the issue persists after upgrade, please [contact our support team](https://thirdweb.com/support) for further assistance.
 </Details>