Bug in notes creation response

There is a bug introduced in b96ca8d9

      # Allow consumers to detect problems applying commands
      note.errors.add(:commands, _('Commands did not apply')) unless message.present?

This is incorrect because message here actually contains both success and error messages. Meaning, if message contained an error, note.errors[:commands] won't be set and then in this block of code:

          if note.errors.keys == [:commands_only]
            status 202
            present note, with: Entities::NoteCommands
          elsif note.valid?
            present note, with: Entities.const_get(note.class.name, false)
          else
            note.errors.delete(:commands_only) if note.errors.has_key?(:commands)
            bad_request!("Note #{note.errors.messages}")
          end

We'd always get a 202 even if the quick actions had some errors.

I think we need to clean up how we pass these messages in the response because passing success messages in a model's error hash is confusing and can lead to wrong assumptions like this. This can be done with #213679 where we want to separate the success and error messages in the frontend.

cc @alexkalderimis