Hello
I have just over a decade experience of working in university accommodation, including dealing with many room moves etc, so just thought I'd offer some thoughts here in case it's helpful
It is unusual the uni have made this placement, at both the unis I have worked in it has always been policy to:
(a) not put students together from the same course, (for reasons of allowing them a healthy work/home balance and also so they have a broader social circle, not seeing the same people constantly! The only exceptions to this i have known are for courses such as nursing etc, where placement schedules are gruelling, and the students tend to have a need to lead a somewhat different/professional lifestyle)
(b) not to put a single student of either gender in with all-girls/all-boys, on the very rare occasion that this has ended up being the case due to voluntary room moves etc, a member of staff would usually have reached out to discuss this with the individual, and we would even get a form signed to say they were happy with this - now not all unis will have the same policy on - but I will say it may be possible that is has occurred purely through human error, as most uni accom allocation systems are still managed manually, and it could be that the person allocating has made a bit of a mistake and not double checked the genders when mass allocating or similar. Usually for an 8 person flat for example, they will have set allocations for the 'gender' of the rooms eg. rooms A, B, C are male, rooms D, E, F are female, and rooms G and H are 'either'. If it is a concern a quick call to their accom office to clarify what their policy is may help, you dont need to give in your info necessarily, you could just ask to double check their policy/stance on allocations
In terms of your initial question, it is likely that the course is mostly male, but their are likely (hopefully!) to be a few other girls on the course and I'm sure they will naturally introduce themselves to one another quite quickly
Your daughter may also want to consider what clubs and societies she is interested in as these are a really good place to start - where possible it's good make sure you make the start of the year events for these as it's easier to make friends and connections when everyone is new at the beginning of the year
There will mostly likely be other flats that are mixed or even all girls nearby, and a quick knock on the door in the first few days in a neighbourly fashion can often strike up friendships in the early days as everyone is in the same boat. The other girls nearby are likely to be very receptive if she explains she's in an all-boys flat and also wants to make some other connections too!
Bigger halls may also some clubs of their own, eg inter halls netball, football, etc will often draw only a small crowd and the halls netball rather than the uni netball will be purely a social thing really, it's not competitive and even if she doesnt have much interest as long as she's not super adverse to it, it can be a good way to meet other people/girls from the halls. There may also be a halls social committee to get involved in if thats her thing - it all depends on her interests!
I cannot see what all the previous comments say as some have already been removed, I'm sorry you have received some unhelpful/inappropriate ones. If you have any further qs I can do my best to answer from a 'generic uni' perspective if helpful.
Sorry for the long post! There's so much going on at the beginning of first year - I hope your daughter has a great time.