Hey there,
I am really sorry for the delay of this reply as it is a weekend for us here.
Unfortunately that was no setting to turn it off but you can modify on this file ->
JoomlaFolder/components/com_easyblog/themes/wireframe/composer/sidebar/actions.php
Remove these line of code :
<?php if ($post->isBlank() || $post->isPublished() || ($post->isDraft() && !$post->isPostUnpublished())) { ?>
<a href="javascript:void(0);" class="btn btn-eb-default btn--lg btn-block btn-draft" data-composer-save-draft>
<?php echo JText::_('COM_EASYBLOG_SAVE_AS_DRAFT_BUTTON');?>
</a>
<?php } ?>
After you modified it, you can copy this modification file override into your current template ->
JoomlaFolder/templates/YourCurrentTemplate/html/com_easyblog/composer/sidebar/actions.php