This is new to me, as I haven't used ServiceDesk.
I tried to re-create your problem, and instead of a simple validator I used a script validator.
After approving a test issue, validator status was still shown as "Has not run yet.", which means JIRA bypasses validators in case of approvals.
So, the answer to your question is No. A workaround may be possible - but there will be compromises.
Although approvals and workflow transitions look visually similar to the end user, JIRA internally organizes approvals in a different way (meta data tags in workflow XML rather than action). I think this gives an indication that conditions and validators won't work here.
What you can do here is, forget approvals feature and create your own transitions called Approve/ Decline. If you have Script Runner add-on you can write a custom validator for 'x number of approvers' feature too.
Badges are a great way to show off community activity, whether you’re a newbie or a Champion.Learn more
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG