Ideally, interaction design deals with the design on the interaction level: what happens when the user interacts with x, and how they will achieve y, where it leads to, site maps, flow, logic, content, etc. It would take a form in wireframes, and/or mockups, sometimes even prototypes. They don't define colors, visuals, styles, typography etc, as that becomes more of a UI designer's role.
In the idealistic approach, "motion/animation designer" is what you would typically label as someone who deals with animations.
Now, thats the idealistic definition The problem with that is the real world requirements aren't so ideal. Companies will always want to hire more competitive candidates, so sometimes a UI designer's role may include animations as part of the job requirement. Sometimes, Interaction designers may need to code. etc etc. What I'm trying to say is while there is a standard definition, or boundary of tasks for each role, trying too hard to draw distinct lines between the different roles will become a limitation in your way of thinking.
so TLDR, an interaction designer typically deals with wireframes, mockups etc
"motion /animation designer" will more or less deal with animations, but it may just be as valid when it becomes a part of UI designer's role too.