Hi. First of all congrats on the invite! and I am sorry about the discrepancy. That's annoying.
I think the best thing is to inform the AdCom ASAP to demonstrate that you have good faith in correcting the issue and restoring the truth. I would not make this long or too apologetic however.
So, not a consultant or a writer but one version I could see would go something like this:
Dear Admissions Team,
I am thrilled to receive an interview invite. In preparation for the interview, reviewing my application, I noticed a discrepancy on the resume that I wanted to bring to your attention. The position listed from 6/2022 to 12/2022 was in fact incorrectly stated as consultant; my official role was "intern consultant". I am attaching an updated version with that correction; all other information is accurate.
I apologize for this discrepancy and completely understand it may cause an inconvenience and have an impact on my application but I felt it was important to make the distinction to accurately reflect my profile.
Thank you for your help,
Your Name.