Great advice there. I think some people get hung up on modules they feel they need to take but as an undergrad do the ones you are interested in, even if it ends up a mixed bag. Sometimes the ‘hands on skill’ modules are useful as the skills are something you will use & are transferable, ie legal writing (if you go into a legal job).
Is your dissertation compulsory in yr 3? Many unis are moving away from this in law, whereby becoming optional. So as the PP says, if you plan on doing a dissertation then maybe it will help, if not then you don’t necessarily need it - it could give you the opportunity to research something you’re interested in that you haven’t covered in Uni yet though - maybe something more in depth you could discuss at an interview etc?
Finally, I’d say if you are interested in legal academics and can see yourself doing an LLM & PhD then I’d definitely go for the research module…