chore(dashboard): update dashboard quickstart for consistency

Author: goosewin

fern/quickstart/dashboard.mdx

@@ -1,6 +1,6 @@
 ---
 title: Dashboard
-subtitle:  Learn to build a voice agent in under 5 minutes.
+subtitle: Learn to build a voice agent in under 5 minutes using the Vapi dashboard.
 slug: quickstart/dashboard
 ---