Assuming the quest wasn't uploaded, you can press undo in the bottom left, it should open a list of recent edits. If it's the last edit you made, hit it again. If you made other edits since, tap on the building with the typo (assuming that's the last thing you did with that particular building), that should select the edit in the undo list, which you can then tap. It'll ask if you're sure, and after you hit undo there, the quest should appear back where it was.

That said, the address overlay I mentioned should also allow you to edit it without needing the quest, whether you've uploaded or not. Again, that's just the hamburger menu in the upper right, overlays, addresses, and tap on the building.

Closing this in case anyone is watching notes in the area, feel free to send me a message directly if you have questions. :)