Should a dismissal from PhD in graduate application be listed as academic misconduct?

"Academic misconduct" is not the same as "Lack of academic performance." "Academic misconduct" is things like claiming undue credit, fabrication of research or sources, outright plagiarism, etc. Simply not making the grades might reflect on your academic aptitude, but (unlike academic misconduct) does not necessarily reflect upon your character.

I believe that failing to meet the grade standards do not constitute an academic misconduct or a behavioral misconduct. In my opinion, those refer to cheating, sabotaging others' research projects etc. So I would answer that in the negative. Actually, I would want to be more sure than a random StackExchange answer in answering that question, so I would contact the department to ask, or ask one of my professors from undergrad/grad school.

By the way, as a word of advice, many schools have a separate section ("other circumstances" etc) for explaining that awful thing on your application. If I were you, I would save my SOP for actually talking about the research that I am interested in, and not make that a place where I make excuses. You have to give them a reason to be excited about you. By explaining your circumstances in the SOP, you lose your best shot, and they would at most feel mediocre about you.