Wrap load_balancing initializer in `ee` block

config/initializers/load_balancing.rb

 # We need to run this initializer after migrations are done so it doesn't fail on CI
-if ActiveRecord::Base.connected? && ActiveRecord::Base.connection.data_source_exists?('licenses')
+
+Gitlab.ee do
+  if ActiveRecord::Base.connected? && ActiveRecord::Base.connection.data_source_exists?('licenses')
     if Gitlab::Database::LoadBalancing.enable?
       Gitlab::Database.disable_prepared_statements
 
@@ -17,4 +19,5 @@ if ActiveRecord::Base.connected? && ActiveRecord::Base.connection.data_source_ex
       end
 
     end
+  end
 end