In #3560, we improved our exam clash detection algorithm. Previously, we only checked for exam start times, but it's possible that an exam's end time overlaps with another exam's start time.

However, the "No Exam Clash (Sem X)" filters in our Module Search page still use the previous detection method. We should change it to the better exam clash detection algorithm.

This will require some elasticsearch-fu. Relevant docs: https://www.elastic.co/guide/en/elasticsearch/reference/8.12/query-dsl-range-query.html