update Theme Builder link to try-everywhere ThoughtSpot URL

Author: yinstardev

modules/ROOT/pages/common/nav.adoc

@@ -25,7 +25,7 @@ Live Playgrounds
 ** link:{{navprefix}}/rest-playground[How to use]
 //** link:{{navprefix}}/graphql-play-ground[GraphQL Playground]
 //** +++<a href="{{previewPrefix}}/api/rest/playgroundV1" target="_blank">REST API v1 Playground</a>+++
-* +++<a href="https://theme-builder-embed-prod.vercel.app/" target="_blank">Theme Builder</a>+++
+* +++<a href="https://try-everywhere.thoughtspot.cloud/v2/#/everywhere/playground/theme-builder" target="_blank">Theme Builder</a>+++
 ** link:{{navprefix}}/theme-builder-doc[How to use]