Certified GKH Gardening Expert
Some of them do. If you were told that they get that tall, then they are likely one of the taller cultivars. Some of them will be marked as "dwarf" or "mini" and they will be shorter.
Unfortunately, they require partial shade in the hot Summer months, and full sun when it cools off some in the Winter. With that being said, they will not do as well as they could in the spot you have described.
They will still grow and may do just fine, but they will probably not perform their best.
Here is an article that will help: https://www.gardeningknowhow.com/ornamental/shrubs/sweet-pea-shrubs/growing-sweet-pea-shrubs.htm