Clarify FK docs (#13562)

Author: wedamija

develop-docs/backend/application-domains/database-migrations/index.mdx

@@ -420,7 +420,7 @@ This second PR will contain only the migration and related boilerplate.
 
 ### Foreign Keys
 
-Creating foreign keys is mostly fine, but for some large/busy tables like `Project`, `Group` it can cause problems due to difficulties in acquiring a lock. You can still create a Django level foreign key though, without creating a database constraint. To do so, set `db_constraint=False` when defining the key.
+Creating foreign keys is mostly fine, but for some large/busy tables like `Project` and `Group` the migration can fail due to difficulties in acquiring a lock on the table. The general procedure here is to retry the migration until it goes through - The migration framework adds a lock acquisition timeout, so it's safe to do this.
 
 ### Renaming Tables