Hey
@applebunny I would not worry too much about this. First of all, it is actually quite hard to cheat in a WG as for many questions even consistently high-scoring candidates will have to 'go with their gut'. Secondly, graduate recruiters are well aware that because of that, the WG scores of the same candidates can significantly vary between different tests. They will also be especially aware of this in the context of an AC, where people in the past will have also struggled with nerves.
Thirdly, the firm will not only be assessing you on your WG performance. As such, if you can show your qualities in the other assessments and you do well, they will be inclined to assume you have the analytic skills to do well in the WG and that if there was a drop in performance in the AC it was likely due to nerves. Fourthly, in my opinion what tends to matter most for AC conversion is what the interviewing partners think of you. If they are impressed, it is not likely you will be rejected simply because of a discrepancy in WG performance.
Finally, even in the very unlikely case where your WG score discrepancy is so significant that they cannot overlook it, if the firm otherwise would have wanted to make you an offer, I do not think they would straight out reject you. I believe it is more likely that they would try to speak with you and possibly schedule further WG assessments to see if the discrepancy can have another explanation besides cheating in the initial test.
Thus, my advice is not to let this cause you anxiety on the day of the AC. Try to go with a positive attitude and know that you are going to absolutely nail it!