I wouldn't necessarily raise it in the interview and instead raise it should you get an offer. If you are asked about it at interview, you can state that you are aware there may be issues given your term dates but that you would look to liaise with your university and the firm to ensure you are able to attend the scheme.
If you receive an offer, your options to discuss with the firm are:
- Ask if alternative vacation scheme dates can be offered instead
- Ask whether you can be considered for a direct TC process instead
- Ask whether the firm could offer a part-time scheme where you only do 20 hours per week
Most universities these days will not mess around with term dates because of their concerns around going against their student visa terms (and risking their licence to be eligible for their students to get student visas) but I have heard of some instances where the candidate is able to get approval from their university where their term dates are effectively changed to allow them to attend an internship. The university effectively gives you a study break with the weeks added at the end of the course or to the next academic year instead.