Restricting fluids will only make her dehydrated and her urine more strong and harder to deal with and eventually can cause a UTI. It really has no impact on the bedwetting either.
She is like tons of other children who don't have the ability to wake up when they need to go. They just are not able to do it yet. She will eventually grow out of this, usually by adolescence when their bladder catches up to the rest of their body. If she is still wetting the bed at 7-8 take her to a Pediatric Urologist. Constipation is the common factor in that age child. The excess poo causes pressure on the bladder and there isn't room for the urine.
My grandson is 11 and still has issues occassionaly, he is embarressed by the situation and doesn't want to wear pull ups so we just have a routine where he takes his shower in the morning. I check his bed for wetness and if it's wet I wash the sheets and put them back on, he has a mattress pad that is plastic on one side and I wash it first because I don't put it the dryer on high but low temp instead. He already feels bad enough for the accident and all he needs is for me to go negative and bossy about this. His self image is already suffering, he can't spend the night at friends, he can't have friends over unless I know in advance so he'll have sheets on his bed, etc....
I recommend you get the overnight pull ups with the Disney Princesses on them. We use them for our 6 yr. old granddaughter and she has not had any leaks. My 3 yr. old grandson wears the overnight pull ups with Buzz Light Year on them and he occassionally has an accident but the last one was the day of my mom's funeral when we drove 150 miles away and attended the funderal and then ate, then drove home. I wasn't thinking about diapers and he leaked into his carseat some. That was all day, so of course he leaked.
So, you just need to uplift her as much as possible, build her self image and ignore the issue of bedwetting so she won't develop mental issues about it. It is something she can't help and will grow out of if it isn't a biological issue. Put pull ups on her so you don't have tons of sheets, blankets, and mattress pads to wash each day, and let her drink whatever she needs.
PS., those bedwetting alarms don't really make any difference either. They just wake everyone up after the fact and then you just have even more sheets to wash the next morning plus everyone is up mulitple times during the night instead of just wearing a pull up and everyone sleeping and not having any extra sheets to wash.