[PRO-218] Dashboard: Add product rebrand banner (#7475)

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## PR-Codex overview
This PR updates the `AnnouncementBanner` component to reflect a rebranding message and a new link to a blog post, replacing the previous announcement about the Nebula App.

### Detailed summary
- Updated `href` to point to "https://blog.thirdweb.com/the-fastest-way-to-build-web3-applications/"
- Changed `label` to "We have re-branded our Engine, Universal Bridge, and Connect products. Please read the full blog post for details on changes"
- Updated `trackingLabel` to "product-rebrand"

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

## Summary by CodeRabbit

* **New Features**
  * Updated the announcement banner to highlight the rebranding of Engine, Universal Bridge, and Connect products, with a link to a detailed blog post.

* **Style**
  * Refreshed banner text and link to reflect the latest product updates.

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

Author: MananTank

apps/dashboard/src/@/components/misc/AnnouncementBanner.tsx

@@ -46,9 +46,9 @@ function AnnouncementBannerUI(props: {
 export function AnnouncementBanner() {
   return (
     <AnnouncementBannerUI
-      href="https://nebula.thirdweb.com/"
-      label="Announcing Nebula App — the most powerful AI for blockchains! Try it now!"
-      trackingLabel="nebula-beta-launch"
+      href="https://blog.thirdweb.com/the-fastest-way-to-build-web3-applications/"
+      label="We have re-branded our Engine, Universal Bridge, and Connect products. Please read the full blog post for details on changes"
+      trackingLabel="product-rebrand"
     />
   );
 }