Remove tap and use simplified method call

lib/api/entities.rb

@@ -513,7 +513,8 @@ module API
       # See https://gitlab.com/gitlab-org/gitlab-ce/issues/42344 for more
       # information.
       expose :merge_status do |merge_request|
-        merge_request.tap(&:check_if_can_be_merged).merge_status
+        merge_request.check_if_can_be_merged
+        merge_request.merge_status
       end
       expose :diff_head_sha, as: :sha
       expose :merge_commit_sha