You're right, this is now a habit. I think the problem is that your daughter is used to nursing to sleep, and when she stirs in the night, can't get to sleep without breastfeeding. This can be remedied by helping your daughter learn to soothe herself to sleep
You say that your daughter can sleep through the night, so now you have to encourage her to do so again.
I suggest continuing to breast feed often, but at bed time, after her bedtime routine, breast feed and then put her down to bed. She will complain and cry, but go in and pat her back after 5 minutes, then leave the room. You will likely have to do this many times the first night, and again the second night, but your baby will not cry herself to death just because you don't allow her to use your breast as a soother!
Start during the day too - lay her down when she is really tired, drowsy but still awake, and pat her back, but leave her in her bed.
If you do not do this, you will have her sleeping with you for years!
I breastfed three babies, and all of them were good sleepers, slept through from midnight to 6 am by about 6 - 8 weeks, then by three months were sleeping from 11pm (last feed) to 7:00am, but I would cuddle them, rock them, sing and dance with them, but I put them in their little beds awake, EVERY TIME, because I truly believe that you should not start a habit that you will one day have to break.
I know that the other answers said let her do this, but that may be okay for them, because it is what they want to do, but it isn't what you want, so you need help to fix what is happening.
Again, I am not saying that your baby won't protest, she will, but if she is fed, dry, warm and tired, the place for her is in her bed.
I should also say that there is a difference between letting a young baby cry and cry unattended, until they fall asleep, but if your baby is tired but just is used to suckling to fall asleep, there is nothing wrong with going in to reassure her every ten minutes, but leaving her where she is.
It is also better to have Daddy on board with this, and perhaps he could be the one to go in to pat your daughter's back, as she knows that you have milk, and he doesn't!