docs(website): add more FAQ question (#1159)

Co-authored-by: Haroen Viaene <hello@haroen.me>

packages/website/docs/migrating-from-legacy.mdx

@@ -118,6 +118,12 @@ Your [legacy config][11] will be parsed to a [Crawler config][12], please use [t
 
 Your credentials will remain available, but **once all the existing configs have been migrated, we will stop the daily crawl jobs**.
 
+### Why do I see two Algolia apps in my dashboard?
+
+We did not remove access to the legacy DocSearch application (`BH4D9OD16A`) to give you the time to get familiar with our new infrastructure. `BH4D9OD16A` will remain available until the migration has been completed for all the DocSearch users.
+
+_Please only refer to your new Algolia application if you already have access_
+
 ### Are the [`docsearch-scraper`][8] and [`docsearch-configs`][9] repository still maintained?
 
 At the time you are reading this, the migration hasn't been completed, so yes they are still maintained.