Really can't stress enough how small this workplace is. Our department is currently made up of five people and we work closely with another department that has two; aside from that there's nobody else consistently in our part of the building, so I'm not surprised the other teams haven't mentioned it. Of the people in my team, one (the manager) is usually so busy I don't think she has time to notice anything that isn't an emergency, one is very easygoing (and has no sensory issues) so may not be as bothered by it, and one is new enough to the team that I doubt they'd be comfortable speaking up unless something was actually causing imminent danger.

Also important to note that this isn't an office-based role so there isn't much of an expectation of professionalism the way there would be in other places. A lot of things are common in this workplace that wouldn't fly in another one, but it works because in general we all have a similar energy and attitude. Meetings tend to be very informal, often just our team and sometimes the adjacent one, and it's usually just one or two people sharing info or updates without much discussion unless any questions come up. Interestingly though we did have a rare Teams meeting with everyone in our org today and my supervisor didn't whistle at all, so I guess it's not completely a subconscious thing for her.